POJ 2777 Count Color

经典的染色问题，很明显的体现了lazy——tag思想...

/*
用cin超时...
*/

#include <stdio.h>
#include <string.h>
#include <iostream>
#include <algorithm>
#define L(t) ((t) << 1)
#define R(t) ((t) << 1 | 1)
using namespace std;

const int MAXN = 1000002;
bool used[33];
struct SegTree
{
    int l, r;
    int color;            //-1多种颜色 否则为单一颜色 
    int getMid(){
        return (l + r) >> 1;
    }
};
SegTree tree[MAXN << 2];
int l, t, o;                //l长度 t种颜色 o次操作

void bulid(int left, int right, int t){
    tree[t].l = left;
    tree[t].r = right;
    tree[t].color = 1;
    if(right == left)
        return;
    int mid = tree[t].getMid();
    bulid(left,mid,L(t));
    bulid(mid + 1, right, R(t));    
}

void insert(int left, int right, int c, int t){
    if(left    <= tree[t].l && right >= tree[t].r){
        tree[t].color = c;
        return;
    }
    if(tree[t].color != -1){            //第二类信息 自上向下传递
        tree[L(t)].color = tree[R(t)].color = tree[t].color;
        tree[t].color = -1;
    }
    int mid = tree[t].getMid();
    if(right <= mid){
        insert(left, right, c, L(t));
    } else if(left > mid){
        insert(left, right, c, R(t));
    } else {
        insert(left, mid, c, L(t));
        insert(mid + 1, right, c, R(t));
    }
}
void query(int left, int right, int t){
        if(tree[t].color > 0){
            used[tree[t].color] = true;
        return;
    }
    int mid = tree[t].getMid();
    if(right <= mid){
        query(left, right, L(t));
    } else if( left > mid){
        query(left, right, R(t));
    } else {
        query(left, mid, L(t));
        query(mid + 1, right, R(t));
    }
}

int main(){
    char cmd[2];
    int a, b, c;
    //cin >> l >> t >> o;
    scanf("%d%d%d",&l,&t,&o);
    bulid(1, l, 1);
    for(int i = 0; i < o; ++i){
        //cin >> cmd;
        scanf("%s",cmd);
        if(cmd[0] == 'C'){
        //    cin >> a >> b >> c;
            scanf("%d%d%d",&a, &b, &c);
            if(a > b)
                a ^= b ^= a ^= b;
            insert(a, b, c, 1);
        } else {
        //      cin >> a >> b;
            scanf("%d%d",&a, &b);
            if(a > b)
                a ^= b ^= a ^= b;
            memset(used, false, sizeof(used));
            query(a, b, 1);
            int cnt = 0;
            for(int i = 0; i <= t; i++)
                if(used[i]){
                    cnt++;
                }
        //    cout << cnt << endl;
            printf("%d\n",cnt);
        }
    }
    return 0;
}