# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
937980 | asdasdqwer | Towns (IOI15_towns) | C++14 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
using namespace std;
#define pii array<int,2>
vector<vector<int>> dis;
map<pii,int> mp;
int query(int a, int b) {
if (mp.find({a,b}) != mp.end()) {
return mp[{a,b}];
}
if (mp.find({b,a}) != mp.end()) {
return mp[{b,a}];
}
int d = getDistance(a, b);
mp[{a,b}] = d;
return d;
}
int hubDistance(int N, int sub) {
dis.assign(N, vector<int>(N, 1e9));
for (int i=0;i<N;i++) {
dis[i][i] = 0;
}
// first N queries
vector<int> lst(N);
for (int i=0;i<N;i++) {
lst[i] = i;
}
random_shuffle(lst.begin(), lst.end());
for (int i=0;i<N;i++) {
int a = lst[i];
int b = lst[(i+1)%N];
dis[a][b] = dis[b][a] = query(a,b);
}
// floyd warshall
for (int k=0;k<N;k++) {
for (int i=0;i<N;i++) {
for (int j=0;j<N;j++) {
dis[i][j] = min(dis[i][j], dis[i][k] + dis[k][j]);
}
}
}
bool found = false;
int retVal = 0;
while (!found) {
// find maximum value and respective nodes
int mxVal = -1;
pii pos = {-1, -1};
for (int i=0;i<N;i++) {
for (int j=i+1;j<N;j++) {
if (dis[i][j] > mxVal) {
mxVal = dis[i][j];
pos = {i, j};
}
}
}
int d = query(pos[0], pos[1]);
if (d == dis[pos[0]][pos[1]]) {
found = true;
retVal = d;
break;
}
dis[pos[0]][pos[1]] = dis[pos[1]][pos[0]] = d;
for (int i=0;i<N;i++) {
dis[i][pos[0]] = min(dis[i][pos[0]], dis[i][pos[1]] + dis[pos[1]][pos[0]]);
dis[i][pos[1]] = min(dis[i][pos[1]], dis[i][pos[0]] + dis[pos[0]][pos[1]]);
}
}
}