【线段树】Codeforces 437B The Child and Set

来源：互联网发布：2017年网络新项目编辑：程序博客网时间：2024/06/03 00:23

题目点这里

vfk大大讲过的 = = 记录一个最大值然后暴力搞就行了。。。

最开始WA了一次是因为Modify没更改最大值。。

#include <cstdio>#include <iostream>#include <cstring>using namespace std;const int Nmax = 1e5 + 5;int N, M;int a[Nmax];#define lc (u << 1)#define rc (u << 1 | 1)namespace SegmentTree {    long long sum[Nmax << 2], mmax[Nmax << 2];        inline long long Max(long long a, long long b) { return a > b ? a : b; }        inline void Push_up(int u)    {        sum[u] = sum[lc] + sum[rc];        mmax[u] = Max(mmax[lc], mmax[rc]);    }        inline void build(int u, int l, int r)    {        if (l == r) {            sum[u] = mmax[u] = a[l];            return;        }        int mid = (l + r) >> 1;        build(lc, l, mid); build(rc, mid + 1, r);        Push_up(u);    }        inline long long Query(int u, int l, int r, int L, int R)    {        if (l == L && r == R) return sum[u];        int mid = (l + r) >> 1;        if (R <= mid) return Query(lc, l, mid, L, R);        else if (L > mid) return Query(rc, mid + 1, r, L, R);        return Query(lc, l, mid, L, mid) + Query(rc, mid + 1, r, mid + 1, R);    }        inline void Mod(int u, int l, int r, int L, int R, int x)    {        if (mmax[u] < x) return;        if (l == r) { sum[u] = mmax[u] = sum[u] % x; return; }        int mid = (l + r) >> 1;        if (R <= mid) Mod(lc, l, mid, L, R, x);        else if (L > mid) Mod(rc, mid + 1, r, L, R, x);        else {            Mod(lc, l, mid, L, mid, x);            Mod(rc, mid + 1, r, mid + 1, R, x);        }        Push_up(u);    }        inline void Modify(int u, int l, int r, int pos, int x)    {        if (l == r) { mmax[u] = sum[u] = x; return; }        int mid = (l + r) >> 1;        if (pos <= mid) Modify(lc, l, mid, pos, x);        else Modify(rc, mid + 1, r, pos, x);        Push_up(u);    }}int main(){    ios :: sync_with_stdio(false);    cin >> N >> M;    for (int i = 1; i <= N; ++i) cin >> a[i];        using namespace SegmentTree;    build(1, 1, N);        for (int sign, l, r, x; M --; ) {        cin >> sign >> l >> r;        if (sign  == 1) cout << Query(1, 1, N, l, r) << endl;        else if (sign == 2) {            cin >> x;            Mod(1, 1, N, l, r, x);        }        else Modify(1, 1, N, l, r);    }        return 0;}

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