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feat: add solutions to lc problem: No.1182. Shortest Distance to Target Color
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‎solution/1100-1199/1182.Shortest Distance to Target Color/README.md

Lines changed: 68 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -46,27 +46,92 @@
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<li><code>1 &lt;= queries[i][1] &lt;= 3</code></li>
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</ul>
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## 解法
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<!-- 这里可写通用的实现逻辑 -->
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二分查找。
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先用哈希表记录每种颜色的索引位置。然后遍历 `queries`，如果当前 `color` 不在哈希表中，说明不存在解决方案，此时此 `query` 对应的结果元素是 `-1`。否则，在哈希表中取出当前 `color` 对应的索引列表，二分查找即可。
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<!-- tabs:start -->
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### **Python3**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```python
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class Solution:
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def shortestDistanceColor(self, colors: List[int], queries: List[List[int]]) -> List[int]:
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color_indexes = collections.defaultdict(list)
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for i, c in enumerate(colors):
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color_indexes[c].append(i)
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res = []
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for i, c in queries:
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if c not in color_indexes:
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res.append(-1)
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else:
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t = color_indexes[c]
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left, right = 0, len(t) - 1
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while left < right:
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mid = (left + right) >> 1
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if t[mid] >= i:
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right = mid
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else:
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left = mid + 1
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val = abs(t[left] - i)
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if left > 0:
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val = min(val, abs(t[left - 1] - i))
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if left < len(t) - 1:
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val = min(val, abs(t[left + 1] - i))
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res.append(val)
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return res
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```
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### **Java**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```java
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class Solution {
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public List<Integer> shortestDistanceColor(int[] colors, int[][] queries) {
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Map<Integer, List<Integer>> colorIndexes = new HashMap<>();
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for (int i = 0; i < colors.length; ++i) {
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int c = colors[i];
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if (!colorIndexes.containsKey(c)) {
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colorIndexes.put(c, new ArrayList<>());
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}
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colorIndexes.get(c).add(i);
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}
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List<Integer> res = new ArrayList<>();
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for (int[] query : queries) {
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int i = query[0], c = query[1];
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if (!colorIndexes.containsKey(c)) {
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res.add(-1);
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continue;
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}
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List<Integer> t = colorIndexes.get(c);
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int left = 0, right = t.size() - 1;
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while (left < right) {
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int mid = (left + right) >> 1;
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if (t.get(mid) >= i) {
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right = mid;
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} else {
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left = mid + 1;
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}
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}
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int val = Math.abs(t.get(left) - i);
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if (left > 0) {
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val = Math.min(val, Math.abs(t.get(left - 1) - i));
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}
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if (left < t.size() - 1) {
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val = Math.min(val, Math.abs(t.get(left + 1) - i));
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}
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res.add(val);
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}
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return res;
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}
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}
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```
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### **...**

‎solution/1100-1199/1182.Shortest Distance to Target Color/README_EN.md

Lines changed: 66 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -43,18 +43,82 @@ The nearest 1 from index 6 is at index 3 (3 steps away).
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## Solutions
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Binary search.
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<!-- tabs:start -->
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### **Python3**
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```python
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class Solution:
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def shortestDistanceColor(self, colors: List[int], queries: List[List[int]]) -> List[int]:
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color_indexes = collections.defaultdict(list)
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for i, c in enumerate(colors):
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color_indexes[c].append(i)
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res = []
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for i, c in queries:
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if c not in color_indexes:
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res.append(-1)
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else:
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t = color_indexes[c]
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left, right = 0, len(t) - 1
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while left < right:
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mid = (left + right) >> 1
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if t[mid] >= i:
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right = mid
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else:
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left = mid + 1
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val = abs(t[left] - i)
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if left > 0:
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val = min(val, abs(t[left - 1] - i))
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if left < len(t) - 1:
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val = min(val, abs(t[left + 1] - i))
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res.append(val)
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return res
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```
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### **Java**
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```java
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class Solution {
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public List<Integer> shortestDistanceColor(int[] colors, int[][] queries) {
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Map<Integer, List<Integer>> colorIndexes = new HashMap<>();
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for (int i = 0; i < colors.length; ++i) {
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int c = colors[i];
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if (!colorIndexes.containsKey(c)) {
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colorIndexes.put(c, new ArrayList<>());
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}
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colorIndexes.get(c).add(i);
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}
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List<Integer> res = new ArrayList<>();
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for (int[] query : queries) {
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int i = query[0], c = query[1];
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if (!colorIndexes.containsKey(c)) {
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res.add(-1);
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continue;
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}
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List<Integer> t = colorIndexes.get(c);
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int left = 0, right = t.size() - 1;
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while (left < right) {
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int mid = (left + right) >> 1;
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if (t.get(mid) >= i) {
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right = mid;
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} else {
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left = mid + 1;
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}
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}
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int val = Math.abs(t.get(left) - i);
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if (left > 0) {
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val = Math.min(val, Math.abs(t.get(left - 1) - i));
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}
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if (left < t.size() - 1) {
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val = Math.min(val, Math.abs(t.get(left + 1) - i));
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}
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res.add(val);
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}
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return res;
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}
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}
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```
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### **...**

‎solution/1100-1199/1182.Shortest Distance to Target Color/Solution.java

Lines changed: 39 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,39 @@
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class Solution {
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public List<Integer> shortestDistanceColor(int[] colors, int[][] queries) {
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Map<Integer, List<Integer>> colorIndexes = new HashMap<>();
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for (int i = 0; i < colors.length; ++i) {
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int c = colors[i];
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if (!colorIndexes.containsKey(c)) {
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colorIndexes.put(c, new ArrayList<>());
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}
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colorIndexes.get(c).add(i);
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}
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List<Integer> res = new ArrayList<>();
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for (int[] query : queries) {
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int i = query[0], c = query[1];
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if (!colorIndexes.containsKey(c)) {
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res.add(-1);
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continue;
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}
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List<Integer> t = colorIndexes.get(c);
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int left = 0, right = t.size() - 1;
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while (left < right) {
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int mid = (left + right) >> 1;
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if (t.get(mid) >= i) {
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right = mid;
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} else {
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left = mid + 1;
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}
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}
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int val = Math.abs(t.get(left) - i);
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if (left > 0) {
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val = Math.min(val, Math.abs(t.get(left - 1) - i));
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}
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if (left < t.size() - 1) {
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val = Math.min(val, Math.abs(t.get(left + 1) - i));
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}
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res.add(val);
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}
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return res;
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}
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}

‎solution/1100-1199/1182.Shortest Distance to Target Color/Solution.py

Lines changed: 25 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,25 @@
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class Solution:
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def shortestDistanceColor(self, colors: List[int], queries: List[List[int]]) -> List[int]:
3+
color_indexes = collections.defaultdict(list)
4+
for i, c in enumerate(colors):
5+
color_indexes[c].append(i)
6+
res = []
7+
for i, c in queries:
8+
if c not in color_indexes:
9+
res.append(-1)
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else:
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t = color_indexes[c]
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left, right = 0, len(t) - 1
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while left < right:
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mid = (left + right) >> 1
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if t[mid] >= i:
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right = mid
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else:
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left = mid + 1
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val = abs(t[left] - i)
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if left > 0:
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val = min(val, abs(t[left - 1] - i))
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if left < len(t) - 1:
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val = min(val, abs(t[left + 1] - i))
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res.append(val)
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return res

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