Submission #146187

#	Time	Username	Problem	Language	Result	Execution time	Memory
146187		popovicirobert	Salesman (IOI09_salesman)	C++14	77 / 100	977 ms	35832 KiB

salesman

#include <bits/stdc++.h>
#define lsb(x) (x & (-x))
#define ll long long
#define ull unsigned long long


#if 0
const int MOD = ;

inline int lgput(int a, int b) {
    int ans = 1;
    while(b > 0) {
        if(b & 1) ans = (1LL * ans * a) % MOD;
        b >>= 1;
        a = (1LL * a * a) % MOD;
    }
    return ans;
}

inline void mod(int &x) {
    if(x >= MOD)
        x -= MOD;
}

inline void add(int &x, int y) {
    x += y;
    mod(x);
}

inline void sub(int &x, int y) {
    x += MOD - y;
    mod(x);
}

inline void mul(int &x, int y) {
    x = (1LL * x * y) % MOD;
}

inline int inv(int x) {
    return lgput(x, MOD - 2);
}
#endif

#if 0
int fact[], invfact[];

inline void prec(int n) {
    fact[0] = 1;
    for(int i = 1; i <= n; i++) {
        fact[i] = (1LL * fact[i - 1] * i) % MOD;
    }
    invfact[n] = lgput(fact[n], MOD - 2);
    for(int i = n - 1; i >= 0; i--) {
        invfact[i] = (1LL * invfact[i + 1] * (i + 1)) % MOD;
    }
}

inline int comb(int n, int k) {
    if(n < k) return 0;
    return (1LL * fact[n] * (1LL * invfact[k] * invfact[n - k] % MOD)) % MOD;
}
#endif

using namespace std;

const int INF = 2e9;
const int MAXN = (int) 5e5;

vector < pair <int, int> > offers[MAXN + 1];

struct SegTree {
    int aint[2 * MAXN + 1];

    inline void init() {
        fill(aint, aint + 2 * MAXN, -INF);
    }

    inline void update(int pos, int val) {
        pos += MAXN - 1;
        aint[pos] = max(aint[pos], val);
        while(pos > 1) {
            pos /= 2;
            aint[pos] = max(aint[2 * pos], aint[2 * pos + 1]);
        }
    }

    inline int query(int l, int r) {
        l += MAXN - 1, r += MAXN;
        int ans = -INF;
        while(l < r) {
            if(l & 1) {
                ans = max(ans, aint[l++]);
            }
            if(r & 1) {
                ans = max(ans, aint[--r]);
            }
            l >>= 1, r >>= 1;
        }
        return ans;
    }

}st1, st2;

int main() {
#if 0
    ifstream cin("A.in");
    ofstream cout("A.out");
#endif
    int i, n, u, d, s;
    //ios::sync_with_stdio(false);
    //cin.tie(0), cout.tie(0);

    //cin >> n >> u >> d >> s;
    scanf("%d%d%d%d" ,&n,&u,&d,&s);
    for(i = 1; i <= n; i++) {
        int t, x, c;
        //cin >> t >> x >> c;
        scanf("%d%d%d" ,&t,&x,&c);
        offers[t].push_back({x, c});
    }

    st1.init(), st2.init();
    st1.update(s, -u * s);
    st2.update(s, d * s);

    for(int t = 1; t <= MAXN; t++) {
        sort(offers[t].begin(), offers[t].end());

        int sz = offers[t].size();
        for(i = 1; i < sz; i++) {
            offers[t][i].second += offers[t][i - 1].second;
        }

        unordered_map <int, int> upd;
        int mx = -INF;
        for(i = 0; i < sz; i++) {
            int x = offers[t][i].first;
            mx = max(mx, st2.query(1, x) - (i > 0 ? offers[t][i - 1].second : 0));
            ll cur = mx + offers[t][i].second - d * x;
            if(upd.find(x) == upd.end() || upd[x] < cur) {
                upd[x] = cur;
            }
        }

        mx = -INF;
        for(i = sz - 1; i >= 0; i--) {
            int x = offers[t][i].first;
            mx = max(mx, st1.query(x, MAXN) + offers[t][i].second);
            ll cur = mx - (i > 0 ? offers[t][i - 1].second : 0) + x * u;
            if(upd.find(x) == upd.end() || upd[x] < cur) {
                upd[x] = cur;
            }
        }

        mx = -INF;
        for(i = 0; i < sz; i++) {
            int x = offers[t][i].first;
            mx = max(mx, x * (d + u) - (i > 0 ? offers[t][i - 1].second : 0) + st1.query(x, MAXN));
            ll cur = mx + offers[t][i].second - d * x;
            if(upd.find(x) == upd.end() || upd[x] < cur) {
                upd[x] = cur;
            }
        }

        mx = -INF;
        for(i = sz - 1; i >= 0; i--) {
            int x = offers[t][i].first;
            mx = max(mx, offers[t][i].second - x * (d + u) + st2.query(1, x));
            ll cur = mx + u * x - (i > 0 ? offers[t][i - 1].second : 0);
            if(upd.find(x) == upd.end() || upd[x] < cur) {
                upd[x] = cur;
            }
        }
        for(auto it : upd) {
            st1.update(it.first, it.second - it.first * u);
            st2.update(it.first, it.second + it.first * d);
        }
    }

    auto get = [&](int a, int b) {
        if(a <= b) return (b - a) * d;
        return (a - b) * u;
    };

    int ans = -INF;
    for(i = 1; i <= MAXN; i++) {
        ans = max(ans, st1.query(i, i) + u * i - get(i, s));
        ans = max(ans, st2.query(i, i) - d * i - get(i, s));
    }
    cout << ans;

    return 0;
}

Compilation message (stderr)

salesman.cpp: In function 'int main()':
salesman.cpp:114:10: 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:118:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d%d" ,&t,&x,&c);
         ~~~~~^~~~~~~~~~~~~~~~~~~~

• Subtask 1: 77 / 100