제출 #386341

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
386341		phathnv	Sjeckanje (COCI21_sjeckanje)	C++11	110 / 110	1230 ms	54764 KiB

Main

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

const int N = 2e5 + 1;
const ll INF = 1e18;

int n, q, a[N];

int getSign(ll x){
    if (x < 0)
        return -1;
    else if (x == 0)
        return 0;
    else
        return 1;
}

struct Node{
    ll val, dp[2][2], leftVal, rightVal;
    Node(){
        val = leftVal = rightVal = 0;
        dp[0][0] = dp[0][1] = dp[1][0] = dp[1][1] = 0;
    }
    void update(ll delta){
        val += delta;
        dp[0][0] = 0;
        dp[1][1] = abs(val);
        dp[0][1] = dp[1][0] = -INF;
        leftVal = rightVal = val;
    }
    Node operator + (const Node &oth){
        Node res;
        res.leftVal = leftVal;
        res.rightVal = oth.rightVal;
        for(int i = 0; i < 2; i++)
            for(int j = 0; j < 2; j++)
                res.dp[i][j] = -INF;
        for(int a = 0; a < 2; a++)
            for(int b = 0; b < 2; b++)
                for(int c = 0; c < 2; c++)
                    for(int d = 0; d < 2; d++){
                        ll val = dp[a][b] + oth.dp[c][d];
                        if (b && c && getSign(rightVal) * getSign(oth.leftVal) == -1)
                            val -= min(abs(rightVal), abs(oth.leftVal));
                        res.dp[a][d] = max(res.dp[a][d], val);
                    }
        return res;
    }
};

struct segmentTree{
    Node d[N * 4];
    void update(int id, int l, int r, int pos, int val){
        if (pos < l || r < pos)
            return;
        if (l == r){
            d[id].update(val);
            return;
        }
        int mid = (l + r) >> 1;
        update(id << 1, l, mid, pos, val);
        update(id << 1 | 1, mid + 1, r, pos, val);
        d[id] = d[id << 1] + d[id << 1 | 1];
    }
    ll solve(){
        return max(max(d[1].dp[0][0], d[1].dp[0][1]), max(d[1].dp[1][0], d[1].dp[1][1]));
    }
} ST;

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin >> n >> q;

    for(int i = 1; i <= n; i++)
        cin >> a[i];
    for(int i = 1; i < n; i++)
        ST.update(1, 1, n - 1, i, a[i + 1] - a[i]);

    while (q--){
        int l, r, x;
        cin >> l >> r >> x;
        if (l > 1)
            ST.update(1, 1, n - 1, l - 1, x);
        if (r < n)
            ST.update(1, 1, n - 1, r, -x);
        cout << ST.solve() << '\n';
    }

    return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 40 / 40
• Subtask 3: 55 / 55