hdu 1754...忘了个getchar()，蛋疼了半天...原来划水也有蛋疼的时候...

#include <stdio.h>
#include <string.h>

const int MAXN = 200005;

typedef struct {
    int l;
    int r;
    int max;
}Node;

Node seg[MAXN * 4];
int Max;

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

void build(int num,int l,int r)
{
    seg[num].l = l;
    seg[num].r = r;
    seg[num].max = -1;

    if ( l == r )
        return;

    int mid = ( l + r ) / 2;
    build(num * 2, l, mid);
    build(num * 2 + 1, mid + 1, r);
}

void update(int num,int id,int value)
{
    if ( seg[num].l == id && seg[num].r == id )
    {
        seg[num].max = value;
        return;
    }
    
    int mid = ( seg[num].l + seg[num].r ) / 2;
    if ( id <= mid )
        update(num * 2, id, value);
    else
        update(num * 2 + 1, id, value);
    
    seg[num].max = fmax(value,seg[num].max);
    
}

void query(int num,int l,int r)
{
    if ( seg[num].l == l && seg[num].r == r )
    {
        Max = fmax(Max,seg[num].max);
        return;
    }

    int mid = ( seg[num].l + seg[num].r ) / 2;
    if ( r <= mid )
        query(num * 2, l, r);
    else if ( mid + 1 <= l )
        query(num * 2 + 1, l, r);
    else
    {
        query(num * 2, l, mid);
        query(num * 2 + 1, mid + 1, r);
    }
}


int main()
{
//    freopen("1.txt","r",stdin);

    int N,M;
    while ( scanf("%d%d",&N,&M) == 2 )
    {
        build(1,1,N);

        int mark;

        for (int i = 1; i <= N; i++)
        {
            scanf("%d",&mark);
            update(1,i,mark);
        }

        char a;
        int b,c;
        while ( M-- )
        {
            getchar();
            scanf("%c%d%d",&a,&b,&c);
            if ( a == 'Q' )
            {
                Max = -1;
                query(1,b,c);
                printf("%d\n",Max);
            }
            else
            {
                update(1,b,c);
            }
        }
    }

    return 0;
}