hdu 4391 Paint The Wall 線段樹

hdu 4391 Paint The Wall

http://acm.hdu.edu.cn/showproblem.php?pid=4391

n個機關長度，m個操作

n個數，表示n個機關長度中起始顔色

m行， a, l, r, z

a== 1表示把l到r塗為z色（z>= 0 && z<= 2^31)

a==2 表示詢問l到r為z色的有多少

用lazy，同時，節點中，加入mi和ma記錄該段中的最大和最小值是多少

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <cmath>
using namespace std;
const int maxn = 100010;
struct node{
    int num, lef, rig, mid, ans, lazy, col, mi, ma;
}seg[maxn*4];
int m, n;
void maketree(int num, int lef, int rig){
    seg[num].lef = lef;
    seg[num].rig = rig;
    seg[num].mid = (lef + rig)>> 1;
    seg[num].lazy = 0;
    seg[num].col = -1;
    seg[num].ans = rig - lef + 1;
    seg[num].mi = -1;
    seg[num].ma = -1;
    if( lef != rig){
        maketree(num*2, lef, seg[num].mid);
        maketree(num*2+ 1, seg[num].mid+1, rig);
    }
}
void insert(int num, int lef, int rig, int col){
    if( seg[num].lef == seg[num].rig){
        seg[num].col = col;
        seg[num].lazy = 1;
        seg[num].mi =col;
        seg[num].ma = col;
        return ;
    }
    if( seg[num].lazy == 1){
        seg[num*2].col = seg[num].col;
        seg[num*2+1].col = seg[num].col;
        seg[num*2].lazy = 1;
        seg[num*2+1].lazy = 1;
        seg[num*2].mi = seg[num].col;
        seg[num*2].ma = seg[num].col;
        seg[num*2+1].mi = seg[num].col;
        seg[num*2+1].ma = seg[num].col;
        seg[num].lazy = 0;
    }
    //這裡注意……ma，mi與lazy更新變化位置相同
    if( seg[num].mi == -1){
        seg[num].mi = col;
        seg[num].ma = col;
    }
    else{
        seg[num].mi = min( seg[num].mi, col);
        seg[num].ma = max( seg[num].ma, col);
    }
    
    if( lef == seg[num].lef && rig == seg[num].rig){
        seg[num].mi = col;
        seg[num].ma = col;
        seg[num].col = col;
        seg[num].lazy = 1;
    }
    else if( rig <= seg[num].mid ){
        insert(num*2, lef, rig, col);
    }
    else if( lef > seg[num].mid){
        insert(num*2+1, lef, rig, col);
    }
    else{
        insert(num*2, lef, seg[num].mid, col);
        insert( num*2+1, seg[num].mid + 1, rig, col);
    }
}
int cal(int num, int lef, int rig, int col){
    if( col < seg[num].mi || col > seg[num].ma) return 0;
    if( lef == seg[num].lef && rig == seg[num].rig){
        if( seg[num].lazy == 1){
            if( seg[num].col == col){
                return seg[num].ans;
            }
            else return 0;
        }
        else{
            return cal(num*2, lef, seg[num].mid, col) + cal(num*2+1, seg[num].mid+1, rig, col);
        }
    }
    //lazy在cal中同樣需要更新
    if( seg[num].lazy == 1){
        seg[num*2].col = seg[num].col;
        seg[num*2+1].col = seg[num].col;
        seg[num*2].mi = seg[num].col;
        seg[num*2+1].mi = seg[num].col;
        seg[num*2].ma = seg[num].col;
        seg[num*2+1].ma = seg[num].col;
        seg[num*2].lazy = 1;
        seg[num*2+1].lazy = 1;
        seg[num].lazy = 0;
    }
    if( rig <= seg[num].mid){
        return cal(num*2, lef, rig, col);
    }
    else if( lef > seg[num].mid){
        return cal(num*2+1, lef, rig, col);
    }
    else{
        return cal(num*2, lef, seg[num].mid, col) + cal(num*2+1, seg[num].mid+1, rig, col);
    }
}
int main(){
	//freopen("1.txt", "r", stdin);
    int i, j, k, aa, bb, cc, dd;
    while( scanf("%d%d", &n, &m) != EOF){
        maketree(1, 0, n-1);
        for( i= 0; i<n; i++){
            scanf("%d", &aa);
            insert( 1, i, i, aa);
        }
        for( i= 0; i<m; i++){
            scanf("%d%d%d%d", &aa, &bb, &cc, &dd);
            if( aa == 2){
                printf("%d\n", cal(1, bb, cc, dd));
            }
            if( aa == 1){
                insert(1, bb, cc, dd);
            }
        }
    }
	return 0;
}