hdu 3308 LCIS（线段树）

LCIS

#include <bits/stdc++.h>
using namespace std;
#define MXN 100010
int n, m, d[MXN]; 
struct sTN{int l, r, mid, lm, m, rm;} tree[MXN<<2];
void up(int root){
    sTN & rt = tree[root];
    sTN & lrt = tree[root<<1];
    sTN & rrt = tree[root<<1|1];
    rt.m = max(lrt.m, rrt.m);
    rt.lm = lrt.lm, rt.rm = rrt.rm;
    if(d[lrt.r] < d[rrt.l]){
        rt.m = max(rt.m, lrt.rm + rrt.lm);
        if(lrt.lm == lrt.r - lrt.l+1)
            rt.lm = lrt.lm + rrt.lm;
        if(rrt.rm == rrt.r - rrt.l+1)
            rt.rm = lrt.rm + rrt.rm;
    }
}
void build(int root, int l, int r){
    sTN & rt = tree[root];
    int mid = (l+r)/2;
    rt.l = l, rt.r = r, rt.mid = mid;
    if(l == r){
        rt.lm = 1, rt.m = 1, rt.rm = 1;
        return;
    }
    build(root<<1, l, mid);
    build(root<<1|1, mid+1, r);
    up(root);
}
void update(int root, int a, int b){
    sTN & rt = tree[root];
    if(rt.l == rt.r) d[a] = b;
    else{
        if(a > rt.mid) update(root<<1|1, a, b);
        else update(root<<1, a, b);
        up(root);
    }    
}
int query(int root, int l, int r){
    sTN & rt = tree[root];
    if(rt.l == l && rt.r == r) return rt.m;
    sTN & lrt = tree[root<<1];
    sTN & rrt = tree[root<<1|1];
    if(rt.mid < l)
        return query(root<<1|1, l, r);
    else if(rt.mid >= r)
        return query(root<<1, l, r);
    else{
        int mx = max(query(root<<1, l, rt.mid), query(root<<1|1, rt.mid+1, r));
        if(d[lrt.r] < d[rrt.l]){
            return max(min(lrt.rm,rt.mid-l+1)+min(rrt.lm, r-rt.mid), mx);
        }
        return mx;
    }
}
int main(){
    int T, a, b;
    char op[10];
    scanf("%d", &T);
    while(T--){
        scanf("%d %d", &n, &m);
        for(int i = 1; i <= n; i++) scanf("%d", d+i);
        build(1, 1, n);
        while(m--){
            scanf("%s %d %d", op, &a, &b);
            if(op[0] == 'U') update(1, a+1, b);
            else printf("%d\n", query(1, a+1, b+1));
        }
    }
    return 0;
}