auto commit

Author: CyC2018

notes/Leetcode 题解.md

@@ -2544,31 +2544,25 @@ Given the above grid map, return 7. Because the path 1→3→1→1→1 minimizes
 
 ```java
 public int minPathSum(int[][] grid) {
-        if (grid.length==0 || grid[0].length == 0) {
-            return 0;
-        }
-        int m = grid.length, n = grid[0].length;
-        int[] dp = new int[n];        
-        for(int i =0;i<m;i++) {
-            for(int j=0;j<n;j++){
-                if(i==0) {
-                    if(j==0) {
-                        dp[j] = grid[i][j];
-                    }
-                    else {
-                    dp[j]=dp[j-1] + grid[i][j];
-                    }
-                }else if(j==0) {
-                    dp[j] = dp[j] + grid[i][j];
-                }
-                else{
-                dp[j] = Math.min(dp[j],dp[j-1])+grid[i][j];
-                }
+    if (grid.length == 0 || grid[0].length == 0) {
+        return 0;
+    }
+    int m = grid.length, n = grid[0].length;
+    int[] dp = new int[n];
+    for (int i = 0; i < m; i++) {
+        for (int j = 0; j < n; j++) {
+            if (j == 0) {
+                dp[j] = dp[j];        // 只能从上侧走到该位置
+            } else if (i == 0) {
+                dp[j] = dp[j - 1];    // 只能从左侧走到该位置
+            } else {
+                dp[j] = Math.min(dp[j - 1], dp[j]);
             }
+            dp[j] += grid[i][j];
         }
-        
-        return dp[n-1];
     }
+    return dp[n - 1];
+}
 ```
 
 **矩阵的总路径数**