Description
Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path.
Note: You can only move either down or right at any point in time.
Example
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| Input:
[
[1,3,1],
[1,5,1],
[4,2,1]
]
Output: 7
Explanation: Because the path 1→3→1→1→1 minimizes the sum.
|
Solution
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| class Solution {
public int minPathSum(int[][] grid) {
if (grid.length == 0 || grid[0].length == 0) return 0;
int m = grid.length;
int n = grid[0].length;
int[][] dp = new int[m][n];
dp[0][0] = grid[0][0];
for (int i = 1; i < m; i++) dp[i][0] = dp[i-1][0] + grid[i][0];
for (int j = 1; j < n; j++) dp[0][j] = dp[0][j-1] + grid[0][j];
for (int i = 1; i < m; i++){
for (int j = 1; j < n; j++){
dp[i][j] = Math.min(dp[i-1][j],dp[i][j-1]) + grid[i][j];
}
}
return dp[m-1][n-1];
}
}
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