POJ 2777 Count Color 线段树 区间更新

题目链接： http://poj.org/problem?id=2777

代码：

#include 
#include 
#include 
#include 
#define sf scanf
#define pf printf
using namespace std;
typedef long long LL;
const int maxn = 100000 + 5;
int col[maxn * 4],laze[4 * maxn];

void init(int n){
    for(int i = 0;i <= 4 * n + 50;++i) col[i] = 2;
    memset(laze,0,sizeof(laze));
}


void PushUp(int rt){
    col[rt] = col[rt << 1] | col[rt << 1 | 1];
}

void PushDown(int rt){
    if(laze[rt]){
        col[rt << 1] = 1 << laze[rt];
        col[rt << 1 | 1] = 1 << laze[rt];
        laze[rt << 1] = laze[rt << 1 | 1] = laze[rt];
        laze[rt] = 0;
    }
}

void update(int rt,int cl,int cr,int l,int r,int v){
    if(l > cr || r < cl) return;                //当前区间完全不包含目标区间
    if(l <= cl && r >= cr){                     //当前区间被目标区间完全包含
        laze[rt] = v;
        col[rt] = 1ll << v;
        return;
    }
    PushDown(rt);
    int mid = (cl + cr) / 2;
    update(rt << 1,cl,mid,l,r,v);
    update(rt << 1|1,mid + 1,cr,l,r,v);
    PushUp(rt);
}

int query(int rt,int cl,int cr,int l,int r){
    if(l > cr || r < cl) return 0;
    if(l <= cl && r >= cr){                     //当前区间被目标区间完全包含
        return col[rt];
    }
    PushDown(rt);
    int mid = (cl + cr) / 2,ret = 0;
    ret = query(rt << 1,cl,mid,l,r);
    ret = ret | query(rt << 1|1,mid + 1,cr,l,r);
    return  ret;
}

int main(){
    int n,t,o;
    while( ~sf("%d%d%d",&n,&t,&o) ){
        getchar();
        init(n);
        char op;
        int x,y,z;
        for(int i = 0;i < o;++i){
            sf("%c %d %d",&op,&x,&y);
            if(x > y) swap(x,y);
            if(op == 'C'){
                sf("%d",&z);
                update(1,1,n,x,y,z);
            }
            else{
                int ret = query(1,1,n,x,y),ans = 0;
                for(int i = 1;i <= t;++i){
                    ans += (ret >> i & 1);
                }
                pf("%d\n",ans);
            }

            getchar();
        }
    }
}