Submission #1105953

#	Time	Username	Problem	Language	Result	Execution time	Memory
1105953		Zero_OP	Catfish Farm (IOI22_fish)	C++17	100 / 100	160 ms	44972 KiB

fish

#include <bits/stdc++.h> //uh may be changing style make it better ?
#ifndef LOCAL
    #include <fish.h>
#endif // LOCAL

using namespace std;

#define sz(v) (int)v.size()
#define all(v) begin(v), end(v)

template<typename T> bool maximize(T& a, const T& b){
    if(a < b) return a = b, true;  return false;
}

long long max_weights(int sizeBoard, int nFishes, vector<int> column, vector<int> row, vector<int> weight){
    vector<vector<pair<int, int>>> fishes(sizeBoard);
    for(int i = 0; i < nFishes; ++i){
        fishes[column[i]].emplace_back(row[i], weight[i]);
    }

    vector<vector<long long>> pref(sizeBoard);
    vector<vector<long long>> up(sizeBoard), down(sizeBoard);
    for(int i = 0; i < sizeBoard; ++i){
        fishes[i].emplace_back(sizeBoard, 0);
        sort(all(fishes[i]));
        pref[i].resize(sz(fishes[i]));
        for(int j = 0; j < sz(fishes[i]); ++j){
            pref[i][j] = (j > 0 ? pref[i][j - 1] : 0) + fishes[i][j].second;
        }

        up[i].resize(sz(fishes[i]));
        down[i].resize(sz(fishes[i]));
    }

    auto prefixSum = [&](int c, int pos) -> long long{
        int l = 0, r = sz(fishes[c]) - 1;
        long long sum = 0;
        assert(!fishes[c].empty());
        while(l <= r){
            int mid = l + r >> 1;
            if(fishes[c][mid].first < pos) sum = pref[c][mid], l = mid + 1;
            else r = mid - 1;
        }

        return sum;
    };

    auto maxAll = [&](int col) -> long long{
        return max(*max_element(all(up[col])), *max_element(all(down[col])));
    };

    //let h[i] be the height of the chosen pier at column i
    for(int i = 1; i < sizeBoard; ++i){

        //calculate the down[i] (case h[i - 1] > h[i])
        long long mx = 0;
        for(int j = sz(fishes[i]) - 1, ptr = sz(fishes[i - 1]) - 1; j >= 0; --j){
            while(ptr >= 0 && fishes[i - 1][ptr].first >= fishes[i][j].first){
                maximize(mx, max(up[i - 1][ptr], down[i - 1][ptr]) + prefixSum(i, fishes[i - 1][ptr].first));
                --ptr;
            }

            maximize(down[i][j], mx - prefixSum(i, fishes[i][j].first));
        }

        //consider h[i - 1] < h[i] and case h[i - 2] > h[i - 1] < h[i]
        mx = (i > 1 ? maxAll(i - 2) : 0);
        for(int j = 0, ptr = 0; j < sz(fishes[i]); ++j){
            while(ptr < sz(fishes[i - 1]) && fishes[i - 1][ptr].first <= fishes[i][j].first){
                maximize(mx, up[i - 1][ptr] - prefixSum(i - 1, fishes[i - 1][ptr].first));
                ++ptr;
            }

            maximize(up[i][j], mx + prefixSum(i - 1, fishes[i][j].first));
        }
    }

    long long ans = 0;
    for(int i = 0; i < sizeBoard; ++i){
        for(int j = 0; j < sz(fishes[i]); ++j){
//            assert(j < sz(up[i]));
//            assert(j < sz(down[i]));
//            cout << "(" << i << ", " << fishes[i][j].first << ") = " << up[i][j] << ' ' << down[i][j] << '\n';
            maximize(ans, max(up[i][j], down[i][j]));
        }
    }

    return ans;
}

#ifdef LOCAL
    int main(){
        freopen("task.inp", "r", stdin);
        freopen("task.out", "w", stdout);

        int n, m;
        cin >> n >> m;
        vector<int> x(m), y(m), z(m);
        for(int i = 0; i < m; ++i) cin >> x[i] >> y[i] >> z[i];

        cout << max_weights(n, m, x, y, z) << '\n';

        return 0;
    }
#endif // LOCAL

Compilation message (stderr)

fish.cpp: In function 'bool maximize(T&, const T&)':
fish.cpp:12:5: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   12 |     if(a < b) return a = b, true;  return false;
      |     ^~
fish.cpp:12:36: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   12 |     if(a < b) return a = b, true;  return false;
      |                                    ^~~~~~
fish.cpp: In lambda function:
fish.cpp:40:25: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   40 |             int mid = l + r >> 1;
      |                       ~~^~~

• Subtask 1: 3 / 3
• Subtask 2: 6 / 6
• Subtask 3: 9 / 9
• Subtask 4: 14 / 14
• Subtask 5: 21 / 21
• Subtask 6: 17 / 17
• Subtask 7: 14 / 14
• Subtask 8: 16 / 16