【ZJOI2005】午餐

题面

https://www.luogu.org/problem/P2577

题解

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
struct node{
  int a,b;
  bool operator < (const node &rhs) const {
    return b>rhs.b;
  }
} t[250];
const int inf=98765;
int n,ans=inf;
int f[205][40250],sum[205];

int dp(int x,int y) {
  if (x>=0&&y>=0 && y<=sum[x]) return f[x][y]; else return inf;
}

int main() {
  int i,j;
  scanf("%d",&n);
  sum[0]=0;
  for (i=1;i<=n;i++) {
    scanf("%d %d",&t[i].a,&t[i].b);
  }
  sort(t+1,t+n+1);
  for (i=1;i<=n;i++) sum[i]=sum[i-1]+t[i].a;
  memset(f,0x3f,sizeof(f));
  f[0][0]=0;
  for (i=1;i<=n;i++) {
      for (j=0;j<=sum[i];j++) f[i][j]=min(max(dp(i-1,j-t[i].a),j+t[i].b),max(dp(i-1,j),sum[i]-j+t[i].b));
  }
  ans=inf;
  for (i=0;i<=sum[n];i++) ans=min(ans,f[n][i]);
  cout<<ans<<endl;
}