Combination sum

Signed-off-by: Leo Ma <begeekmyfriend@gmail.com>

Author: begeekmyfriend

039_combination_sum/combination_sum.c

@@ -40,8 +40,8 @@ static int** combinationSum(int* candidates, int candidatesSize, int target, int
 
 int main(int argc, char **argv)
 {
-    if (argc <= 2) {
-        fprintf(stderr, "Usage: ./test target array...\n");
+    if (argc < 3) {
+        fprintf(stderr, "Usage: ./test target n1 n2...\n");
         exit(-1);
     }
 

040_combination_sum_ii/combination_sum.c

@@ -51,6 +51,11 @@ static int** combinationSum(int* candidates, int candidatesSize, int target, int
 
 int main(int argc, char **argv)
 {
+    if (argc < 3) {
+        fprintf(stderr, "Usage: ./test target n1 n2...\n");
+        exit(-1);
+    }
+
     int i, j, count = 0;
     int target = atoi(argv[1]);
     int *nums = malloc((argc - 2) * sizeof(int));

216_combination_sum_iii/Makefile

@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test combination_sum.c

216_combination_sum_iii/combination_sum.c

@@ -0,0 +1,65 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+
+static void dfs(int *nums, int size, int start, int target, int num, 
+                int *solution, int len, int **results, int *column_sizes, int *count)
+{
+    int i;
+    if (len == num) {
+        if (target == 0) {
+            results[*count] = malloc(len * sizeof(int));
+            memcpy(results[*count], solution, len * sizeof(int));
+            column_sizes[*count] = len;
+            (*count)++;
+        }
+    } else if (target > 0) {
+        for (i = start; i < size; i++) {
+            solution[len] = nums[i];
+            dfs(nums, size, i + 1, target - nums[i], num, solution, len + 1, results, column_sizes, count);
+        }
+    }
+}
+
+/**
+ ** Return an array of arrays of size *returnSize.
+ ** The sizes of the arrays are returned as *columnSizes array.
+ ** Note: Both returned array and *columnSizes array must be malloced, assume caller calls free().
+ **/
+static int** combinationSum3(int k, int n, int** columnSizes, int* returnSize)
+{
+    int i, count = 9;
+    int *nums = malloc(count * sizeof(int));
+    for (i = 0; i < count; i++) {
+        nums[i] = i + 1;
+    }
+
+    int *solution = malloc(k * sizeof(int));
+    int **results = malloc(100 * sizeof(int *));
+    *columnSizes = malloc(100 * sizeof(int));
+    *returnSize = 0;
+    dfs(nums, count, 0, n, k, solution, 0, results, *columnSizes, returnSize);
+    return results;
+}
+
+int main(int argc, char **argv)
+{
+    if (argc != 3) {
+        fprintf(stderr, "Usage: ./test k n\n");
+        exit(-1);
+    }
+
+    int i, j;
+    int k = atoi(argv[1]);
+    int n = atoi(argv[2]);
+    int *sizes, count = 0; 
+    int **lists = combinationSum3(k, n, &sizes, &count);
+    for (i = 0; i < count; i++) {
+        for (j = 0; j < sizes[i]; j++) {
+            printf("%d ", lists[i][j]);
+        }
+        printf("\n");
+    }
+    return 0;
+}