AC日记——The Child and Sequence codeforces 250D

D - The Child and Sequence

思路：

　　因为有区间取模操作所以没法用标记下传；

　　我们发现，当一个数小于要取模的值时就可以放弃；

　　凭借这个来减少更新线段树的次数；

来，上代码：

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>

using namespace std;

#define maxn 100005
#define ll long long

struct TreeNodeType {
    ll l, r, mid, dis, max;
};
struct TreeNodeType tree[maxn << 2];

ll n,m;

inline void in(ll &now)
{
    char Cget = getchar(); now = 0;
    while (Cget > '9' || Cget < '0') Cget = getchar();
    while (Cget >= '0'&&Cget <= '9')
    {
        now = now * 10 + Cget - '0';
        Cget = getchar();
    }
}

void tree_build(ll now, ll l, ll r)
{
    tree[now].l = l, tree[now].r = r;
    if (l == r)
    {
        in(tree[now].dis);
        tree[now].max = tree[now].dis;
        return;
    }
    tree[now].mid = l + r >> 1;
    tree_build(now << 1, l, tree[now].mid);
    tree_build(now << 1 | 1, tree[now].mid + 1, r);
    tree[now].dis = tree[now << 1].dis + tree[now << 1 | 1].dis;
    tree[now].max = max(tree[now << 1].max, tree[now << 1 | 1].max);
}

void tree_to(ll now, ll to,ll x)
{
    if (tree[now].l == tree[now].r)
    {
        tree[now].dis = x;
        tree[now].max = x;
        return;
    }
    if (to <= tree[now].mid) tree_to(now << 1, to, x);
    else tree_to(now << 1 | 1, to, x);
    tree[now].dis = tree[now << 1].dis + tree[now << 1 | 1].dis;
    tree[now].max = max(tree[now << 1].max, tree[now << 1 | 1].max);
}

void tree_mod(ll now, ll l, ll r, ll x)
{
    if (tree[now].max < x) return;
    if (tree[now].l >= l&&tree[now].r <= r) tree[now].dis %= x, tree[now].max %= x;
    if (tree[now].l == tree[now].r) return;
    if (l <= tree[now].mid) tree_mod(now << 1, l, r, x);
    if (r > tree[now].mid) tree_mod(now << 1|1, l, r, x);
    tree[now].dis = tree[now << 1].dis + tree[now << 1 | 1].dis;
    tree[now].max = max(tree[now << 1].max, tree[now << 1 | 1].max);
    //cout <<"^ "<< l << ' ' << r << ' ' << tree[now].dis << ' ' << tree[now].max << endl;
}

ll tree_query(ll now, ll l, ll r)
{
    if (tree[now].l == l&&tree[now].r == r) return tree[now].dis;
    if (l > tree[now].mid) return tree_query(now << 1 | 1, l, r);
    else if (r <= tree[now].mid) return tree_query(now << 1, l, r);
    else return tree_query(now << 1, l, tree[now].mid) + tree_query(now << 1 | 1, tree[now].mid + 1, r);
}

int main()
{
    in(n), in(m);
    tree_build(1, 1, n);
    ll op, u, v, x;
    for (; m--;)
    {
        in(op),in(u),in(v);
        if (op == 1) printf("%lld
", tree_query(1, u, v));
        if (op == 2) in(x), tree_mod(1, u, v, x);
        if (op == 3) tree_to(1, u, v);
    }
    return 0;
}