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];
}