hdu 2795 线段树

比较简单的线段树，查询的时候如果左子树够的话就向左递归，否则向右递归，到叶子时终止。

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;

const int N = 200001;
int h, w, n;

int max( int x, int y )
{
    return x > y ? x : y;
}

struct Node 
{
    int l, r, maxn;
} node[N << 2];

void build( int i, int l, int r )
{
    node[i].l = l, node[i].r = r, node[i].maxn = w;
    if ( l == r ) return ;
    int mid = ( l + r ) >> 1;
    build( i << 1, l, mid );
    build( i << 1 | 1, mid + 1, r );
}

int query( int i, int len )
{
    if ( node[i].l == node[i].r ) 
    {
        node[i].maxn -= len;
        return node[i].l;
    }
    int r;
    if ( node[i << 1].maxn >= len ) 
    {
        r = query( i << 1, len );
    }
    else
    {
        r = query( i << 1 | 1, len );
    }
    node[i].maxn = max( node[i << 1].maxn, node[i << 1 | 1].maxn );
    return r;
}

int main ()
{
    while ( scanf("%d%d%d", &h, &w, &n) != EOF )
    {
        if ( h < n ) build( 1, 1, h );
        else build( 1, 1, n );
        for ( int i = 1; i <= n; i++ )
        {
            int len;
            scanf("%d", &len);
            if ( node[1].maxn < len )
            {
                printf("-1
");
            }
            else
            {
                int ans = query( 1, len );
                printf("%d
", ans);
            }
        }
    }
    return 0;
}