POJ 1088
思路:记忆化搜索 + DP
#include<iostream> #include<cstdio> #include<cstring> #define MAX 105 using namespace std; const int dir[4][2] = {-1, 0, 1, 0, 0, -1, 0, 1}; int map[MAX][MAX], vis[MAX][MAX], h[MAX][MAX]; void dfs(int x, int y){ for(int i = 0;i < 4;i ++){ int xx = x + dir[i][0]; int yy = y + dir[i][1]; if(map[xx][yy] != -1 && map[x][y] > map[xx][yy]){ if(!vis[xx][yy]){ dfs(xx, yy); h[x][y] = max(h[x][y], h[xx][yy] + 1); vis[x][y] = 1; }else{ h[x][y] = max(h[xx][yy] + 1, h[x][y]); continue; } } } } int main(){ int R, C, ans; freopen("in.c", "r", stdin); while(cin >> R >> C){ memset(map, -1, sizeof(map)); memset(vis, 0, sizeof(vis)); for(int i = 1; i<= R;i ++){ for(int j = 0;j <= C;j ++) h[i][j] = 1; } ans = -1; for(int i = 1;i <= R;i ++) for(int j = 1;j <= C;j ++) cin >> map[i][j]; for(int i = 1;i <= R;i ++){ for(int j = 1;j <= C;j ++){ if(!vis[i][j]) dfs(i, j); } } for(int i = 1;i <= R;i ++){ for(int j = 1;j <= C;j ++) ans = max(h[i][j], ans); } cout << ans << endl; } return 0; }