Fix a bug in the Minimum Path Sum solution

youmark · web-flow · commit 497812bd4232 · 2018-09-17T23:40:06.000-07:00
Check boundary
diff --git a/notes/Leetcode 题解.md b/notes/Leetcode 题解.md
@@ -2505,9 +2505,9 @@ public int minPathSum(int[][] grid) {
     for (int i = 0; i < m; i++) {
         for (int j = 0; j < n; j++) {
             if (i == 0) {
-                dp[j] = dp[j - 1];
+                if (j>0) dp[j] = dp[j - 1];
             } else {
-                dp[j] = Math.min(dp[j - 1], dp[j]);
+                if (j>0) dp[j] = Math.min(dp[j - 1], dp[j]);
             }
             dp[j] += grid[i][j];
         }

Original file line number	Diff line number	Diff line change
`@@ -2505,9 +2505,9 @@ public int minPathSum(int[][] grid) {`
`2505`	`2505`	`for (int i = 0; i < m; i++) {`
`2506`	`2506`	`for (int j = 0; j < n; j++) {`
`2507`	`2507`	`if (i == 0) {`
`2508`		`- dp[j] = dp[j - 1];`
	`2508`	`+ if (j>0) dp[j] = dp[j - 1];`
`2509`	`2509`	`} else {`
`2510`		`- dp[j] = Math.min(dp[j - 1], dp[j]);`
	`2510`	`+ if (j>0) dp[j] = Math.min(dp[j - 1], dp[j]);`
`2511`	`2511`	`}`
`2512`	`2512`	`dp[j] += grid[i][j];`
`2513`	`2513`	`}`