标签：动归 minimum max question can init mic number write
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. Notice You can only move either down or right at any point in time. Have you met this question in a real interview? Yes Example Tags Dynamic Programming Related Problems Easy Triangle 26 % Medium Binary Tree Maximum Path Sum
矩阵的动归, 要初始化边界
public int minPathSum(int[][] grid) {
// write your code here
if (grid == null || grid.length == 0) {
return -1;
}
int n = grid.length;
int m = grid[0].length;
//state
int[][] sum = new int[n][m];
//initialize
sum[0][0] = grid[0][0];
for (int i = 1; i < m; i++) {
sum[0][i] = sum[0][i - 1] + grid[0][i];
}
for (int i = 1; i < n; i++) {
sum[i][0] = sum[i - 1][0] + grid[i][0];
}
//top down
for (int i = 1; i < n; i++) {
for (int j = 1; j < m; j++) {
sum[i][j] = Math.min(sum[i - 1][j], sum[i][j - 1]) + grid[i][j];
}
}
//ans
return sum[n - 1][m - 1];
}
标签：动归 minimum max question can init mic number write
原文地址：http://www.cnblogs.com/apanda009/p/7290839.html
