从一个铺满字符A(中间有很多个障碍物 '#')大小为
网格的左上角走到网格的右下角(只能向右或向下走),请返回有多少不同的路径。
保证答案在
范围内。
[[A,A,A],[A,#,A],[A,A,A]]
2
从左上角到右下角一共有2条不同的路径:
1. 向右 -> 向右 -> 向下 -> 向下
2. 向下 -> 向下 -> 向右 -> 向右
[[A,#,A]]
0
从左上角到右下角没有路径可以到达
#include <climits> #include <vector> class Solution { public: /** * 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可 * * * @param obstacleGrid char字符型vector<vector<>> * @return int整型 */ int uniquePathsWithObstacles(vector<vector<char> >& obstacleGrid) { // write code here int m = obstacleGrid.size(); int n = obstacleGrid[0].size(); if(obstacleGrid[0][0] == '#' || obstacleGrid[m - 1][n - 1] == '#'){ return 0; } vector<vector<int>> dp(m + 1, vector<int>(n + 1, 0)); for(int i = 1; i <= m; i++){ if (obstacleGrid[i - 1][0] == '#') { break; } dp[i][1] = 1; } for(int j = 1; j <= n; j++){ if (obstacleGrid[0][j - 1] == '#') { break; } dp[1][j] = 1; } for(int i = 2; i <= m; i++){ for(int j = 2; j <= n; j++){ if (obstacleGrid[i - 1][j - 1] == '#') { dp[i][j] = 0; }else { dp[i][j] = dp[i - 1][j] + dp[i][j - 1]; dp[i][j] %= 2147483648; } } } return dp[m][n]; } };
import java.util.*; public class Solution { public int uniquePathsWithObstacles (ArrayList<ArrayList<Integer>> obstacleGrid) { int m = obstacleGrid.size(), n = obstacleGrid.get(0).size(); int[][] dp = new int[m][n]; dp[0][0] = obstacleGrid.get(0).get(0); for(int i=1; i<m; i++) { if(obstacleGrid.get(i).get(0)==1) dp[i][0] = dp[i-1][0]; else dp[i][0] = 0; } for(int i=1; i<n; i++) { if(obstacleGrid.get(0).get(i)==1) dp[0][i] = dp[0][i-1]; else dp[0][i] = 0; } for(int i=1; i<m; i++){ for(int j=1; j<n; j++){ if(obstacleGrid.get(i).get(j)==1) dp[i][j] = dp[i-1][j] + dp[i][j-1]; else dp[i][j] = 0; } } return dp[m-1][n-1]; } }
function uniquePathsWithObstacles( obstacleGrid ) { // write code here const m = obstacleGrid.length; const n = obstacleGrid[0].length; const dp = new Array(m).fill(0).map(() => new Array(n).fill(0)); for(let i = 0; i < n && obstacleGrid[0][i] != 0; i++) { dp[0][i] = 1; } for(let i = 0; i < m && obstacleGrid[i][0] != 0; i++) { dp[i][0] = 1; } for(let i = 1; i < m; i++) { for(let j = 1; j < n; j++) { if(obstacleGrid[i][j] != 0) { dp[i][j] = (dp[i - 1][j] + dp[i][j - 1]) % 2147483648; } } } return dp[m - 1][n - 1]; }