HDU 1754 I Hate It

AC Code:

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

const int N = 200005; struct node{int l,r,maxn;}
tree[n<<2];

int a[n];
    void build (int m,int l,int r) {tree[m].l = l;
    TREE[M].R = R;
        if (L = = r) {TREE[M].MAXN = a[l];
    return;
    } int mid = (l+r) >>1;
    Build (M<<1,l,mid);
    Build ((m<<1) |1,mid+1,r);
TREE[M].MAXN = Max (tree[m<<1].maxn,tree[(m<<1) |1].MAXN);
        } void Update (int m,int x,int val) {if (TREE[M].L = = x && TREE[M].R = = x) {tree[m].maxn = val;
    return;
    } int mid = (TREE[M].L+TREE[M].R) >>1;
    if (x <= mid) update (M&LT;&LT;1,X,VAL);
    else Update ((m<<1) |1,x,val);
TREE[M].MAXN = Max (tree[m<<1].maxn,tree[(m<<1) |1].MAXN);
    } int query (int m,int l,int R) {if (TREE[M].L = = L && TREE[M].R = = r) return TREE[M].MAXN; int mid = (TREE[M].L+TREE[M].R) >>1;
    if (R <= mid) return query (M&LT;&LT;1,L,R);
    if (L > Mid) return query ((m<<1) |1,l,r);
Return max (query (m<<1,l,mid), query ((m<<1) |1,mid+1,r));
    } int main () {int n,m;
        while (~SCANF ("%d%d", &n,&m)) {for (int i = 1; I <= n; i++) scanf ("%d", &a[i]);
        Build (1,1,n);
        Char op[10];
        int x, y;
            while (m--) {scanf ("%s%d%d", op,&x,&y);
            if (op[0] = = ' Q ') {printf ("%d\n", Query (1,x,y));
            } else if (op[0] = = ' U ') {update (1,x,y);
}}} return 0; }