Submission #112392

#	Time	Username	Problem	Language	Result	Execution time	Memory
112392		evpipis	Salesman (IOI09_salesman)	C++17	100 / 100	968 ms	45448 KiB

salesman

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

#define fi first
#define se second
#define pb push_back
#define mp make_pair
typedef long long ll;
typedef pair<int, int> ii;

const int len = 5e5+5, mx = 5e5+1;
const ll inf = 1e17;
pair<ii, int> arr[len];
ll dp[len][2], tree[2][4*len];

void update(int p, int l, int r, int i, ll v, int t){
    if (l == r)
        tree[t][p] = v;
    else{
        int mid = (l+r)/2;
        if (i <= mid)
            update(2*p, l, mid, i, v, t);
        else
            update(2*p+1, mid+1, r, i, v, t);

        tree[t][p] = max(tree[t][2*p], tree[t][2*p+1]);
    }
}

ll query(int p, int l, int r, int i, int j, int t){
    if (r < i || j < l)
        return -inf;
    if (i <= l && r <= j)
        return tree[t][p];

    int mid = (l+r)/2;
    return max(query(2*p, l, mid, i, j, t), query(2*p+1, mid+1, r, i, j, t));
}

int main(){
    int n, u, d, s;
    scanf("%d %d %d %d", &n, &u, &d, &s);
    for (int i = 1; i <= n; i++)
        scanf("%d %d %d", &arr[i].fi.fi, &arr[i].fi.se, &arr[i].se);
    arr[0] = mp(mp(0, s), 0);
    arr[n+1] = mp(mp(len, s), 0);

    sort(arr+1, arr+n+1);

    for (int i = 0; i < 4*mx; i++)
        tree[0][i] = tree[1][i] = -inf;

    update(1, 0, mx, s, +s*u, 0);
    update(1, 0, mx, s, -s*d, 1);
    for (int i = n, j = n+1; i >= 0; i--, j--){
        while (i-1 >= 0 && arr[i-1].fi.fi == arr[i].fi.fi)
            i--;
        while (j-1 >= 0 && arr[j-1].fi.fi == arr[j].fi.fi)
            j--;

        for (int k = i; k < j; k++){
            dp[k][1] = dp[k][0] = max(query(1, 0, mx, 0, arr[k].fi.se, 0)-u*arr[k].fi.se, query(1, 0, mx, arr[k].fi.se, mx, 1)+arr[k].fi.se*d);
            if (k != i)
                dp[k][0] = max(dp[k][0], dp[k-1][0] - (arr[k].fi.se-arr[k-1].fi.se)*u + arr[k-1].se);
        }

        for (int k = j-1; k >= i; k--){
            if (k != j-1)
                dp[k][1] = max(dp[k][1], dp[k+1][1] - (arr[k+1].fi.se-arr[k].fi.se)*d + arr[k+1].se);
        }

        for (int k = i; k < j; k++){
            update(1, 0, mx, arr[k].fi.se, max(dp[k][0], dp[k][1])+arr[k].se+arr[k].fi.se*u, 0);
            update(1, 0, mx, arr[k].fi.se, max(dp[k][0], dp[k][1])+arr[k].se-arr[k].fi.se*d, 1);
        }
    }

    printf("%lld\n", dp[0][0]);
    return 0;
}

Compilation message (stderr)

salesman.cpp: In function 'int main()':
salesman.cpp:42:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d %d", &n, &u, &d, &s);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
salesman.cpp:44:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d %d", &arr[i].fi.fi, &arr[i].fi.se, &arr[i].se);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100