[Ultraviolet A] 1232-Skyline (line segment tree branch reduction)

Note that you also need to use a TR [I] to record the node value and Col [I] to record whether the node interval is fully covered.

#include<cstdio>#include<cstring>#include<algorithm>using namespace std;const int maxn = 111111;const int maxd = 100001;#define lson pos<<1#define rson pos<<1|1int col[maxn << 2];int  tr[maxn << 2];int ret;void pushdown(int pos){    if(col[pos] != -1){        tr[lson] = col[pos]; tr[rson] = col[pos];        col[lson]= col[pos]; col[rson]= col[pos];        col[pos] = -1;    }    return;}void Query(int L,int R,int l,int r,int pos,int value){    if(col[pos] != -1 && tr[pos] > value) return;  //这个减枝非常重要，如果不加就TLE了    if(col[pos] != -1){         //这个区间是一个统一区间        if(L <= l && r <= R){             if(value >= tr[pos]){                ret += (r - l + 1);                tr[pos] = value;  //区间赋值                col[pos]= value;  //懒惰标记             }            return;        }    }    pushdown(pos);    int m = (l + r) >> 1;    if(L <= m)        Query(L,R,l,m,lson,value);    if(R  > m)        Query(L,R,m + 1,r,rson,value);}int main(){    int T;    scanf("%d",&T);    while(T--){        int n = 0,m;        ret = 0;        scanf("%d",&m);        memset(col,0,sizeof(col));        memset(tr,0,sizeof(tr));        for(int i = 0; i < m; i++){            int L,R,v;            scanf("%d%d%d",&L,&R,&v);            Query(L,R - 1,1,maxd,1,v);        }        printf("%d\n",ret);    }    return 0;}

[Ultraviolet A] 1232-Skyline (line segment tree branch reduction)