老师要求用dp,大佬们,帮帮孩子吧!!!
我的0分代码awa:
#include <bits/stdc++.h>
using namespace std;
const int N=1002;
string f[N][N];
char a[N][N];
int kk[N][N];
int main(){
freopen("treasure.in","r",stdin);
freopen("treasure.out","w",stdout);
int n,k;
std::cin >>n>>k;
for(int i=1;i<=n;i++)
for(int j=1;j<=n;j++)
std::cin >>a[i][j];
if(a[1][1]!='a'&&k>0)f[1][1]="a",k--;
else f[1][1]=a[1][1];
kk[1][1]=k;
for(int i=1;i<=n;i++){
for(int j=1;j<=n;j++){
if(i==1&&j==1)continue;
if(f[i][j-1]>f[i-1][j]){
f[i][j]=f[i-1][j];
kk[i][j]=kk[i-1][j];
}
else if(f[i][j-1]<f[i-1][j]){
f[i][j]=f[i][j-1];
kk[i][j]=kk[i][j-1];
}
else {
f[i][j]=f[i][j-1];
kk[i][j]=max(kk[i][j-1],kk[i-1][j]);
}
if(a[i][j]!='a'&&kk[i][j]>0)f[i][j]+='a',kk[i][j]--;
else f[i][j]+=a[i][j];
}
}
std::cout <<f[n][n];
return 0;
}