Submission #154842

#	Time	Username	Problem	Language	Result	Execution time	Memory
154842		Sensei	Divide and conquer (IZhO14_divide)	C++14	100 / 100	203 ms	26356 KiB

divide

#include <bits/stdc++.h>

using namespace std;

const int N = 1e5;

class SegmentTree {
    private:
        long long tree[4 * 2 * N + 7];

        int mid (int ss, int se) {
            return (ss + se) >> 1;
        }

        void upd (int ss, int se, int si, int i, long long k) {
            if (ss == se) {
                tree[si] = max(tree[si], k);
            }
            else {
                if (i <= mid(ss, se)) {
                    upd (ss, mid(ss, se), si * 2, i, k);
                }
                else {
                    upd (mid(ss, se) + 1, se, si * 2 + 1, i, k);
                }

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

        long long qry (int ss, int se, int si, int qs, int qe) {
            if (ss > qe || qs > se) {
                return 0;
            }

            if (qs <= ss && se <= qe) {
                return tree[si];
            }

            return max(qry(ss, mid(ss, se), si * 2, qs, qe), qry(mid(ss, se) + 1, se, si * 2 + 1, qs, qe));
        }
    
    public:
        void update (int i, long long k) {
            upd(1, 2 * N, 1, i, k);
        }

        long long query (int qs, int qe) {
            return qry(1, 2 * N, 1, qs, qe);
        }

        void clear () {
            memset(tree, 0, sizeof tree);
        }
};

int x[N + 7];
int g[N + 7];
int e[N + 7];
long long pree[N + 7];
long long preg[N + 7];
map<long long, int> newv;

int main () {
    int n;
    cin >> n;

    for (int i = 1; i <= n; i++) {
        scanf("%d %d %d", &x[i], &g[i], &e[i]);
    }

    for (int i = 1; i <= n; i++) {
        pree[i] = pree[i - 1] + e[i];
        preg[i] = preg[i - 1] + g[i];
    }

    vector<long long> values;

    for (int i = 1; i <= n; i++) {
        values.push_back(pree[i] - x[i]);
        values.push_back(pree[i - 1] - x[i] + 1);
    }

    sort(values.begin(), values.end());

    int currv = 1;

    newv[values[0]] = currv;

    for (int i = 1; i < values.size(); i++) {
        if (values[i] != values[i - 1]) {
            currv++;
        }

        newv[values[i]] = currv;
    }

    long long ans = 0;
    SegmentTree segtree;
    segtree.clear();

    for (int i = n; i >= 1; i--) {
        // cerr << "i: " << i << " " << pree[i] << " " << x[i] << " " << preg[i] << endl;
        ans = max(ans, 1LL * g[i]);
        segtree.update(newv[pree[i] - x[i]], preg[i]);
        // cerr << "x: " << newv[pree[i] - x[i]] << endl;
        ans = max(ans, segtree.query(newv[pree[i - 1] - x[i] + 1], 2 * N) - preg[i - 1]);
        // cerr << "y: " << newv[pree[i - 1] - x[i] + 1] << endl;
        // cerr << "qry: " << segtree.query(newv[pree[i - 1] - x[i] + 1], 2 * N) << endl;
    }

    cout << ans << endl;

    return 0;
}
/*
4
0 5 1
1 7 2
4 4 1
7 15 1
*/
/*
2
0 4 1
3 5 1
*/

Compilation message (stderr)

divide.cpp: In function 'int main()':
divide.cpp:90:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 1; i < values.size(); i++) {
                     ~~^~~~~~~~~~~~~~~
divide.cpp:69:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d %d", &x[i], &g[i], &e[i]);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 17 / 17
• Subtask 2: 31 / 31
• Subtask 3: 52 / 52