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Submission #436243

# Submission time Handle Problem Language Result Execution time Memory
436243 2021-06-24T10:56:39 Z Popax21 Distributing Candies (IOI21_candies) C++17
100 / 100
 526 ms 35024 KB 
#include <bits/stdc++.h>

// same as the nlog2 solution, except that we do binary search on the segment tree
using namespace std;

const int n_bits=19;
const long long inf = 1e18;
long long minseg[1<<(n_bits+1)];
long long maxseg[1<<(n_bits+1)];
long long lazyadd[1<<(n_bits+1)];

// a standard lazy propagation segment tree
// here we need to support both min and max
// so it is essentially 2 segtrees combined together
// but we only need 1 copy of lazy add
struct segtree {
    long long last_value = 0;
    long long small = inf;
    long long big = -inf;

    segtree() {}

    void update(int node, int change) { // treated as a suffix update
        last_value += change;
        node += (1<<n_bits);
        lazyadd[node] += change;
        while(node>1) {
            if(node%2==0) {
                lazyadd[node+1] += change;
            }
            minseg[node/2] = min(minseg[node]+lazyadd[node], minseg[node^1]+lazyadd[node^1]);
            maxseg[node/2] = max(maxseg[node]+lazyadd[node], maxseg[node^1]+lazyadd[node^1]);
            node = node/2;
        }
    }

    int solve(int capacity) { // returns the largest index i, such that the range >= c
        int node = 1;
        small = inf;
        big = -inf;
        long long lz = 0;
        while(node < (1<<n_bits)) {
            lz += lazyadd[node];
            node *= 2;
            if(max(big, maxseg[node+1]+lazyadd[node+1]+lz) - min(small, minseg[node+1]+lazyadd[node+1]+lz) > capacity) {
                node++;
            } else {
                big = max(big, maxseg[node+1]+lazyadd[node+1]+lz);
                small = min(small, minseg[node+1]+lazyadd[node+1]+lz);
            }
        }
        if(minseg[node] + lazyadd[node] + lz < last_value) {
            return capacity - (big - last_value);
        } else {
            return last_value - small;
        }
    }
};

vector<pair<int,int>> toggle[(int)6e5];
// this tells you what you need to toggle on/off as you move across the boxes
// stores a pair indicating the query id and the change in number of candies
vector<int> distribute_candies(vector<int> C, vector<int> L, vector<int> R, vector<int> V) {
    int n = C.size();
    int q = L.size();
    segtree s;

    for(int i=0; i<q; i++) {
        toggle[L[i]].push_back(make_pair(i, V[i]));
        toggle[R[i]+1].push_back(make_pair(i, -V[i]));
    }

    vector<int> ans;
    ans.resize(n);
    for(int i=0; i<n; i++) {
        for(pair<int,int> p: toggle[i]) {
            s.update(p.first+2, p.second); // store values as if the boxes have infinite capacity
        }

        if(maxseg[1] - minseg[1] < C[i]) { // easy case: range is small
            ans[i] = s.last_value - (minseg[1] + lazyadd[1]);
        } else { // we binary search on the segtree
            ans[i] = s.solve(C[i]);
        }
    }
    return ans;
}

Subtask #1
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 14540 KB Output is correct
2 Correct 10 ms 14540 KB Output is correct
3 Correct 13 ms 14796 KB Output is correct
4 Correct 12 ms 14668 KB Output is correct
5 Correct 13 ms 14748 KB Output is correct

Subtask #2
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 526 ms 34948 KB Output is correct
2 Correct 391 ms 34948 KB Output is correct
3 Correct 399 ms 34944 KB Output is correct

Subtask #3
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 14528 KB Output is correct
2 Correct 194 ms 30064 KB Output is correct
3 Correct 123 ms 18228 KB Output is correct
4 Correct 438 ms 34928 KB Output is correct
5 Correct 383 ms 34884 KB Output is correct
6 Correct 397 ms 34948 KB Output is correct
7 Correct 381 ms 34956 KB Output is correct

Subtask #4
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 14540 KB Output is correct
2 Correct 11 ms 14540 KB Output is correct
3 Correct 101 ms 28760 KB Output is correct
4 Correct 80 ms 17196 KB Output is correct
5 Correct 175 ms 31068 KB Output is correct
6 Correct 176 ms 31024 KB Output is correct
7 Correct 190 ms 31008 KB Output is correct
8 Correct 171 ms 31056 KB Output is correct
9 Correct 189 ms 30988 KB Output is correct

Subtask #5
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 14540 KB Output is correct
2 Correct 10 ms 14540 KB Output is correct
3 Correct 13 ms 14796 KB Output is correct
4 Correct 12 ms 14668 KB Output is correct
5 Correct 13 ms 14748 KB Output is correct
6 Correct 526 ms 34948 KB Output is correct
7 Correct 391 ms 34948 KB Output is correct
8 Correct 399 ms 34944 KB Output is correct
9 Correct 11 ms 14528 KB Output is correct
10 Correct 194 ms 30064 KB Output is correct
11 Correct 123 ms 18228 KB Output is correct
12 Correct 438 ms 34928 KB Output is correct
13 Correct 383 ms 34884 KB Output is correct
14 Correct 397 ms 34948 KB Output is correct
15 Correct 381 ms 34956 KB Output is correct
16 Correct 10 ms 14540 KB Output is correct
17 Correct 11 ms 14540 KB Output is correct
18 Correct 101 ms 28760 KB Output is correct
19 Correct 80 ms 17196 KB Output is correct
20 Correct 175 ms 31068 KB Output is correct
21 Correct 176 ms 31024 KB Output is correct
22 Correct 190 ms 31008 KB Output is correct
23 Correct 171 ms 31056 KB Output is correct
24 Correct 189 ms 30988 KB Output is correct
25 Correct 11 ms 14540 KB Output is correct
26 Correct 81 ms 17096 KB Output is correct
27 Correct 195 ms 30048 KB Output is correct
28 Correct 397 ms 34960 KB Output is correct
29 Correct 406 ms 34880 KB Output is correct
30 Correct 381 ms 34944 KB Output is correct
31 Correct 426 ms 35008 KB Output is correct
32 Correct 379 ms 35024 KB Output is correct