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Submission #649104

# Submission time Handle Problem Language Result Execution time Memory
649104 2022-10-09T10:26:47 Z ponkung Distributing Candies (IOI21_candies) C++17
100 / 100
 300 ms 35068 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 8 ms 14548 KB Output is correct
2 Correct 8 ms 14548 KB Output is correct
3 Correct 9 ms 14676 KB Output is correct
4 Correct 9 ms 14676 KB Output is correct
5 Correct 11 ms 14816 KB Output is correct

Subtask #2
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 293 ms 35000 KB Output is correct
2 Correct 266 ms 34960 KB Output is correct
3 Correct 274 ms 35068 KB Output is correct

Subtask #3
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 14548 KB Output is correct
2 Correct 175 ms 29952 KB Output is correct
3 Correct 71 ms 18304 KB Output is correct
4 Correct 300 ms 35004 KB Output is correct
5 Correct 274 ms 34964 KB Output is correct
6 Correct 260 ms 34960 KB Output is correct
7 Correct 266 ms 34880 KB Output is correct

Subtask #4
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 14524 KB Output is correct
2 Correct 8 ms 14548 KB Output is correct
3 Correct 84 ms 28808 KB Output is correct
4 Correct 62 ms 17212 KB Output is correct
5 Correct 136 ms 31068 KB Output is correct
6 Correct 134 ms 31068 KB Output is correct
7 Correct 141 ms 31072 KB Output is correct
8 Correct 130 ms 31072 KB Output is correct
9 Correct 138 ms 31028 KB Output is correct

Subtask #5
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 14548 KB Output is correct
2 Correct 8 ms 14548 KB Output is correct
3 Correct 9 ms 14676 KB Output is correct
4 Correct 9 ms 14676 KB Output is correct
5 Correct 11 ms 14816 KB Output is correct
6 Correct 293 ms 35000 KB Output is correct
7 Correct 266 ms 34960 KB Output is correct
8 Correct 274 ms 35068 KB Output is correct
9 Correct 8 ms 14548 KB Output is correct
10 Correct 175 ms 29952 KB Output is correct
11 Correct 71 ms 18304 KB Output is correct
12 Correct 300 ms 35004 KB Output is correct
13 Correct 274 ms 34964 KB Output is correct
14 Correct 260 ms 34960 KB Output is correct
15 Correct 266 ms 34880 KB Output is correct
16 Correct 8 ms 14524 KB Output is correct
17 Correct 8 ms 14548 KB Output is correct
18 Correct 84 ms 28808 KB Output is correct
19 Correct 62 ms 17212 KB Output is correct
20 Correct 136 ms 31068 KB Output is correct
21 Correct 134 ms 31068 KB Output is correct
22 Correct 141 ms 31072 KB Output is correct
23 Correct 130 ms 31072 KB Output is correct
24 Correct 138 ms 31028 KB Output is correct
25 Correct 8 ms 14548 KB Output is correct
26 Correct 61 ms 17184 KB Output is correct
27 Correct 150 ms 29940 KB Output is correct
28 Correct 252 ms 34896 KB Output is correct
29 Correct 275 ms 34936 KB Output is correct
30 Correct 299 ms 34884 KB Output is correct
31 Correct 278 ms 35016 KB Output is correct
32 Correct 279 ms 35064 KB Output is correct