HDU-6668-Game 百度之星第一场B

#include<iostream>
#include<string.h>
#include<algorithm>
#include<stdio.h>
#include<vector>
#define pii pair<int,int>
#define pb push_back
#define mp make_pair
#define LL long long
using namespace std;
vector<pii>v;
const int maxx = 1005;
int a[maxx];
int b[maxx];
int n;
LL go(int x){
   LL ans=0;
   for(int i=1;i<v.size();i++){
      if (v[i].first>x){
          ans+=(v[i].first-x+1)/2;
          if (i<v.size()-1){
             if ((v[i].first-x)%2){ ///长度为奇数
                 if (v[i+1].first>v[i].second && v[i].second-v[i].first>0){
                    x=v[i].first+1;
                 }else x=v[i].first;
             }else x=v[i].first;
          }else x=v[i].first;
      }else {
          ans+=(x-v[i].second+1)/2;
          if (i<v.size()-1){
              if ((x-v[i].second)%2){
                 if(v[i+1].second<v[i].first && v[i].second-v[i].first>0){
                    x=v[i].second-1;
                 }else x=v[i].second;
              }else x=v[i].second;
          }else x=v[i].second;
      }
   }
   return ans;
}
int main(){
  int t;
  scanf("%d",&t);
  while(t--){
    v.clear();
    scanf("%d",&n);
    scanf("%d%d",&a[1],&b[1]);
    int l=a[1],r=b[1];
    for (int i=2;i<=n;i++){
        scanf("%d%d",&a[i],&b[i]);
        if (a[i]<=r && b[i]>=l){
            l=max(l,a[i]);
            r=min(r,b[i]);
        }else {
            v.pb(mp(l,r));
            l=a[i];
            r=b[i];
        }
    }
    v.pb(mp(l,r));
    LL ans=2e18;
    ans=min(ans,go(v[0].first));
    ans=min(ans,go(v[0].second));
    printf("%lld\n",ans);
  }
  return 0;
}