FOJ 1968 Twinkling lights III

线段树，嗯，嗯。

 

本题有5个操作，并且对象都是区间：1. 开灯 2.关灯 3.把开的关，关的打开 4.询问区间有几盏灯亮着 5.询问区间最多连续亮着几盏灯

 

结构体里的cov是否完全覆盖，-1表示未完全覆盖，0表示区间的灯都暗着，1表示区间灯都亮着。

 

#include <iostream>using namespace std;#define MAX 2000000#define LL(x) (x<<1)#define RR(x) (x<<1|1)#define Mid(a,b) ((a+b)>>1)int cnt,ri,k;struct node{int l,r,mid;int cov;}tree[MAX+10];void build(int l,int r,int num){tree[num].l=l;tree[num].r=r;tree[num].cov=1;if(l==r)return;else{int mid=tree[num].mid=Mid(l,r);build(l,mid,LL(num));build(mid+1,r,RR(num));}}void turn(int l,int r,int num,int ans){if(ans==tree[num].cov)return;if(l==tree[num].l&&r==tree[num].r){tree[num].cov=ans;return;}if(tree[num].cov!=-1){tree[LL(num)].cov=tree[RR(num)].cov=tree[num].cov;tree[num].cov=-1;}int mid=tree[num].mid;if(r<=mid)turn(l,r,LL(num),ans);else if(l>mid)turn(l,r,RR(num),ans);else{turn(l,mid,LL(num),ans);turn(mid+1,r,RR(num),ans);}}void change(int l,int r,int num){if(tree[num].l==l&&tree[num].r==r){if(tree[num].cov!=-1){tree[num].cov^=1;return;}}if(tree[num].cov!=-1){tree[LL(num)].cov=tree[RR(num)].cov=tree[num].cov;tree[num].cov=-1;}int mid=tree[num].mid;if(r<=mid)change(l,r,LL(num));else if(l>mid)change(l,r,RR(num));else{change(l,mid,LL(num));change(mid+1,r,RR(num));}}int count(int l,int r,int num){if(tree[num].cov!=-1){return (r-l+1)*tree[num].cov;}int mid=tree[num].mid;if(r<=mid)count(l,r,LL(num));else if(l>mid)count(l,r,RR(num));elsereturn count(l,mid,LL(num))+count(mid+1,r,RR(num));}void query(int l,int r,int num){if(tree[num].l==l&&tree[num].r==r){if(tree[num].cov!=-1){if(tree[num].cov==1){if(l==ri+1)cnt+=r-l+1;elsecnt=r-l+1;if(cnt>k)k=cnt;ri=r;}return;}}if(tree[num].cov!=-1){tree[LL(num)].cov=tree[RR(num)].cov=tree[num].cov;}int mid=tree[num].mid;if(r<=mid)query(l,r,LL(num));else if(l>mid)query(l,r,RR(num));else{query(l,mid,LL(num));query(mid+1,r,RR(num));}}int main(){int n,m,i,l,r;char ch;while(scanf("%d%d",&n,&m)!=EOF){build(1,n,1);while(m--){scanf(" %c%d%d",&ch,&l,&r);if(ch=='C')turn(l,r,1,0);else if(ch=='S')turn(l,r,1,1);else if(ch=='A')change(l,r,1);else if(ch=='Q')printf("%d/n",count(l,r,1));else if(ch=='L'){k=cnt=0;ri=-1;query(l,r,1);printf("%d/n",k);}}}return 0;}