【SHOI2002】【Luogu1434】滑雪(记忆化)
原创
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problem
solution
codes
//f[i][j]:以(i,j)为终点的最长路是是多少
//f[i][j] = f(它四周的比他高的方块的最长路)+1
#include<iostream>
#include<cstring>
using namespace std;
const int maxn = 110;
int r, c, a[maxn][maxn], f[maxn][maxn], ans;
const int dx[] = {1,0,-1,0};
const int dy[] = {0,-1,0,1};
bool inside(int x, int y){return x>=1&&x<=r&&y>=1&&y<=c;}
int dp(int x, int y){
if(f[x][y])return f[x][y];
int res = 0;
for(int i = 0; i < 4; i++){
int nx = x+dx[i], ny = y+dy[i];
if(inside(nx,ny)&&a[nx][ny]>a[x][y]){
res = max(res,dp(nx,ny));
}
}
return f[x][y]=res+1;//我竟然因为没有更新f[x][y]导致第二个点没过。。
}
int main(){
ios::sync_with_stdio(false);
cin>>r>>c;
for(int i = 1; i <= r; i++)
for(int j = 1; j <= c; j++)
cin>>a[i][j];
for(int i = 1; i <= r; i++)
for(int j = 1; j <= c; j++)
ans = max(ans,dp(i,j));
cout<<ans;
return 0;
}