LeetCode 576. 出界的路径数
原题链接
中等
作者:
我是java同学
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2023-12-29 16:58:04
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所有人可见
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阅读 42
const int N = 55, mod = 1e9 + 7;
class Solution {
public:
typedef long long LL;
int n, m;
int dx[4] = {-1, 0, 1, 0}, dy[4] = {0, 1, 0, -1};
int cache[N][N][N];
LL dfs (int x, int y, int k) {
if (x < 0 || x >= n || y < 0 || y >= m) return 1;
if (!k) return 0;
if (cache[x][y][k] != -1) return cache[x][y][k];
LL res = 0;
for (int i = 0; i < 4; i ++ ) {
int a = x + dx[i], b = y + dy[i];
res += dfs(a, b, k - 1);
res %= mod;
}
cache[x][y][k] = res;
return res;
}
int findPaths(int r, int c, int maxMove, int startRow, int startColumn) {
n = r, m = c;
//初始化记忆数组
for (int i = 0; i < n; i ++ )
for (int j = 0; j < m; j ++ )
for (int k = 0; k <= maxMove; k ++ )
cache[i][j][k] = -1;
return dfs(startRow, startColumn, maxMove) % mod;
}
};