【HDOJ】1556 Color the ball

简单线段树。

#include <stdio.h>

#define MAXN 100005
#define lson l, mid, rt<<1
#define rson mid+1, r, rt<<1|1

int cols[MAXN<<2], leaf;

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

void build(int l, int r, int rt) {
    int mid;
    cols[rt] = 0;
    if (l == r)
        return ;
    mid = (l+r)>>1;
    build(lson);
    build(rson);
}

void update(int ll, int rr, int l, int r, int rt) {
    int mid;

    if (ll<=l && rr>=r) {
        cols[rt]++;
        return ;
    }
    PushDown(rt);
    mid = (l+r)>>1;
    if (ll <= mid)
        update(ll, rr, lson);
    if (rr > mid)
        update(ll, rr, rson);
}

void query(int l, int r, int rt) {
    int mid;
    if (l == r) {
        if (leaf)
            printf(" %d", cols[rt]);
        else
            printf("%d", cols[rt]);
        ++leaf;
        return ;
    }
    PushDown(rt);
    mid = (l+r)>>1;
    query(lson);
    query(rson);
}

int main() {
    int n;
    int i, x, y;

    while (scanf("%d",&n)!=EOF && n) {
        build(1, n, 1);
        for (i=0; i<n; ++i) {
            scanf("%d %d", &x, &y);
            update(x,y,1,n,1);
        }
        leaf = 0;
        query(1, n, 1);
        printf("
");
    }

    return 0;
}