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Submission #434977

# Submission time Handle Problem Language Result Execution time Memory
434977 2021-06-22T17:19:01 Z model_code Distributing Candies (IOI21_candies) C++17
100 / 100
 451 ms 35016 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 11 ms 14540 KB Output is correct
3 Correct 11 ms 14708 KB Output is correct
4 Correct 15 ms 14668 KB Output is correct
5 Correct 13 ms 14804 KB Output is correct

Subtask #2
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 397 ms 34948 KB Output is correct
2 Correct 390 ms 34952 KB Output is correct
3 Correct 408 ms 34888 KB Output is correct

Subtask #3
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 14548 KB Output is correct
2 Correct 205 ms 29948 KB Output is correct
3 Correct 95 ms 18236 KB Output is correct
4 Correct 399 ms 34884 KB Output is correct
5 Correct 387 ms 34884 KB Output is correct
6 Correct 399 ms 35016 KB Output is correct
7 Correct 377 ms 34928 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 12 ms 14540 KB Output is correct
3 Correct 105 ms 28804 KB Output is correct
4 Correct 83 ms 17208 KB Output is correct
5 Correct 165 ms 31064 KB Output is correct
6 Correct 184 ms 31016 KB Output is correct
7 Correct 170 ms 31144 KB Output is correct
8 Correct 163 ms 31064 KB Output is correct
9 Correct 203 ms 31020 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 11 ms 14540 KB Output is correct
3 Correct 11 ms 14708 KB Output is correct
4 Correct 15 ms 14668 KB Output is correct
5 Correct 13 ms 14804 KB Output is correct
6 Correct 397 ms 34948 KB Output is correct
7 Correct 390 ms 34952 KB Output is correct
8 Correct 408 ms 34888 KB Output is correct
9 Correct 11 ms 14548 KB Output is correct
10 Correct 205 ms 29948 KB Output is correct
11 Correct 95 ms 18236 KB Output is correct
12 Correct 399 ms 34884 KB Output is correct
13 Correct 387 ms 34884 KB Output is correct
14 Correct 399 ms 35016 KB Output is correct
15 Correct 377 ms 34928 KB Output is correct
16 Correct 10 ms 14540 KB Output is correct
17 Correct 12 ms 14540 KB Output is correct
18 Correct 105 ms 28804 KB Output is correct
19 Correct 83 ms 17208 KB Output is correct
20 Correct 165 ms 31064 KB Output is correct
21 Correct 184 ms 31016 KB Output is correct
22 Correct 170 ms 31144 KB Output is correct
23 Correct 163 ms 31064 KB Output is correct
24 Correct 203 ms 31020 KB Output is correct
25 Correct 10 ms 14512 KB Output is correct
26 Correct 84 ms 17148 KB Output is correct
27 Correct 221 ms 29940 KB Output is correct
28 Correct 368 ms 34880 KB Output is correct
29 Correct 451 ms 34888 KB Output is correct
30 Correct 437 ms 34944 KB Output is correct
31 Correct 414 ms 35000 KB Output is correct
32 Correct 428 ms 35000 KB Output is correct