Submission #1105318

#	Time	Username	Problem	Language	Result	Execution time	Memory
1105318		InvMOD	Sjeckanje (COCI21_sjeckanje)	C++14	110 / 110	278 ms	30792 KiB

Main

#include<bits/stdc++.h>

#define int long long

using namespace std;

using ll = long long;

const int N = 2e5+5;
const ll inf = 1e16;

int n, q, a[N], sub[N], dp[3][N], st[N<<2][2][2];

int get_dp()
{
    // dp[0]: sum of segment
    // dp[1]: creating segment min -> max
    // dp[2]: creating segment max -> min
    dp[0][0] = 0;
    dp[1][0] = dp[2][0] = -inf;

    for(int i = 1; i <= n; i++){
        dp[0][i] = max({dp[0][i-1], dp[1][i-1] + a[i], dp[2][i-1] - a[i]});
        dp[1][i] = max(dp[1][i-1], dp[0][i-1] - a[i]);
        dp[2][i] = max(dp[2][i-1], dp[0][i-1] + a[i]);
    }
    return dp[0][n];
}

//[0][0]: has the different sign with both start and end
//[0][1]: has the different sign with start and same with end
//[1][0]: has the same sign with start and different with end
//[1][1]: has the same sign with both start and end

void update(int id, int l, int r, int x){
    if(l == r){
        st[id][1][1] = (sub[l] < 0 ? -sub[l] : sub[l]);
        return;
    }
    else{
        int m = l+r>>1;
        if(x <= m) update(id<<1, l, m, x);
        else
            update(id<<1|1, m+1, r, x);

        // if mid sign and mid+1 sign is different
        if(sub[m] * sub[m+1] < 0){
            // our task is to make sure that mid sign and mid+1 sign always the same
            st[id][0][0] = max(st[id<<1][0][1] + st[id<<1|1][0][0], st[id<<1][0][0] + st[id<<1|1][1][0]);
            st[id][0][1] = max(st[id<<1][0][1] + st[id<<1|1][0][1], st[id<<1][0][0] + st[id<<1|1][1][1]);
            st[id][1][0] = max(st[id<<1][1][1] + st[id<<1|1][0][0], st[id<<1][1][0] + st[id<<1|1][1][0]);
            st[id][1][1] = max(st[id<<1][1][1] + st[id<<1|1][0][1], st[id<<1][1][0] + st[id<<1|1][1][1]);
        }
        else{
            // we can take anything from [L,MID], [R,MID]
            st[id][0][0] = max(st[id<<1][0][1], st[id<<1][0][0]) + max(st[id<<1|1][1][0], st[id<<1|1][0][0]);
            st[id][0][1] = max(st[id<<1][0][1], st[id<<1][0][0]) + max(st[id<<1|1][1][1], st[id<<1|1][0][1]);
            st[id][1][0] = max(st[id<<1][1][1], st[id<<1][1][0]) + max(st[id<<1|1][1][0], st[id<<1|1][0][0]);
            st[id][1][1] = max(st[id<<1][1][1], st[id<<1][1][0]) + max(st[id<<1|1][1][1], st[id<<1|1][0][1]);
        }
    }
    return;
}

void solve()
{
    cin >> n >> q;
    for(int i = 1; i <= n; i++){
        cin >> a[i];
        if(i-1){
            sub[i] = a[i] - a[i-1];
            update(1, 2, n, i);
        }
    }

   while(q--){
        int l,r,x; cin >> l >> r >> x;

        sub[l] += x;
        update(1, 2, n, l);

        if(r+1 <= n){
            sub[r+1] -= x;
            update(1, 2, n, r+1);
        }

        cout << max({st[1][0][0], st[1][0][1], st[1][1][0], st[1][1][1]}) <<"\n";
    }
    return;
}

int32_t main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    #define name "InvMOD"
    if(fopen(name".INP", "r")){
        freopen(name".INP", "r", stdin);
        freopen(name".OUT", "w", stdout);
    }

    solve();
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'void update(long long int, long long int, long long int, long long int)':
Main.cpp:41:18: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   41 |         int m = l+r>>1;
      |                 ~^~
Main.cpp: In function 'int32_t main()':
Main.cpp:98:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   98 |         freopen(name".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:99:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   99 |         freopen(name".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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