【bzoj4071】[Apio2015]巴邻旁之桥 三分套三分

三分一下第一座桥，三分一下第二座桥，貌似就解决了。

UOJ跑的死慢，bz也T掉了。

#include<cstdio>#include<cstring>#include<cstdlib>#include<cmath>#include<algorithm>#include<iostream>#define maxn 100010 #define inf 1000000000000000using namespace std;struct yts{int op1,x1,op2,x2;}a[maxn];int n,m,k,mx;long long ans;char s[10];long long calc(int x,int y){long long ans=0;for (int i=1;i<=n;i++)  if (a[i].op1==a[i].op2) ans+=abs(a[i].x2-a[i].x1);  else ans+=min(abs(a[i].x2-x)+abs(a[i].x1-x),abs(a[i].x2-y)+abs(a[i].x1-y))+1;return ans;}long long solve(int x){long long ans=0;if (k==1){for (int i=1;i<=n;i++)  if (a[i].op1==a[i].op2) ans+=abs(a[i].x2-a[i].x1);  else ans+=abs(a[i].x2-x)+abs(a[i].x1-x)+1;}else{int l=0,r=mx;while (r-l>=3){int mid=l+(r-l)/3,midmid=r-(r-l)/3;if (calc(x,mid)<=calc(x,midmid)) r=midmid; else l=mid;}ans=inf;for (int i=l;i<=r;i++) ans=min(ans,calc(x,i));}return ans;}int main(){scanf("%d%d",&k,&n);for (int i=1;i<=n;i++){scanf("%s%d",s,&a[i].x1);if (s[0]=='A') a[i].op1=0; else a[i].op1=1;scanf("%s%d",s,&a[i].x2);if (s[0]=='A') a[i].op2=0; else a[i].op2=1;mx=max(mx,max(a[i].x1,a[i].x2));}int l=0,r=mx;while (r-l>=3){int mid=l+(r-l)/3,midmid=r-(r-l)/3;if (solve(mid)<=solve(midmid)) r=midmid; else l=mid;}ans=inf;for (int i=l;i<=r;i++) ans=min(ans,solve(i));printf("%lld\n",ans);return 0;}