UVa 12299 RMQ with Shifts

题目链接：

线段树，点修改。

#include <cstdio>
#include <cctype>
#define lson l, m, rt << 1
#define rson m + 1, r, ( rt << 1 ) | 1

const int MAXN = 100010;
const int INF = 2147483645;

int tree[ MAXN << 2 ];

int min( int a, int b )
{
    return a < b ? a : b;
}

void PushUP( int rt )
{
    tree[rt] = min( tree[rt << 1] , tree[ rt << 1 | 1 ] );
    return;
}

void build( int l, int r, int rt )
{
    if ( l == r )
    {
        scanf( "%d", &tree[rt] );
        return;
    }
    int m = ( l + r ) >> 1;
    build(lson);
    build(rson);
    PushUP(rt);
}

void update( int p, int e, int l, int r, int rt )
{
    if ( l == r )
    {
        tree[rt] = e;
        return;
    }
    int m = ( l + r ) >> 1;
    if ( p <= m ) update( p, e, lson );
    else update( p, e, rson );
    PushUP(rt);
    return;
}

void GetNum( int p, int &e, int l, int r, int rt )
{
    if ( l == r )
    {
        e = tree[rt];
        return;
    }
    int m = ( l + r ) >> 1;
    if ( p <= m ) GetNum( p, e, lson );
    else GetNum( p, e, rson );
    return;
}

int Query( int L, int R, int l, int r, int rt )
{
    if ( L <= l && R >= r )
       return tree[rt];

    int ret = INF;
    int m = ( l + r ) >> 1;
    if ( L <= m ) ret = min( ret, Query( L, R, lson ) );
    if ( R > m ) ret = min( ret, Query( L, R, rson ) );
    return ret;
}

int main()
{
    int n, Q;
    char order[50];
    int addr[50], number[50];
    while ( ~scanf( "%d%d", &n, &Q ) )
    {
        build( 1, n, 1 );
        while ( Q-- )
        {
            scanf( "%s", order );
            if ( order[0] == 'q' )
            {
                int x, y;
                sscanf( order, "query(%d,%d)", &x, &y );
//                printf("##%d %d\n", x, y);
                printf( "%d\n", Query( x, y, 1, n, 1 ) );
            }
            else
            {
                int cnt = 0;
                for ( int i = 0; order[i]; )
                {
                    if ( isdigit( order[i] ) )
                    {
                        int sum = 0;
                        while ( isdigit( order[i] ) )
                            sum = sum * 10 + order[i++] - '0';
                        addr[cnt++] = sum;
                    }
                    else ++i;
                }

                for ( int i = 0; i < cnt; ++i )
                {
               //     printf( "=%d ", addr[i] );
                    GetNum( addr[i], number[i], 1, n, 1 );
               //     printf( "@%d\n", number[i] );
                }
                for ( int i = 0; i < cnt; ++i )
                {
                    if ( i == cnt - 1 ) update( addr[i], number[0], 1, n, 1 );
                    else update( addr[i], number[i + 1], 1, n, 1 );
                }
            }
        }
    }
    return 0;
}