# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
91384 | mirbek01 | Marriage questions (IZhO14_marriage) | C++11 | 1570 ms | 12424 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;
const int N = 1e5 + 2;
int n, m, k, mt[N], used[N], ans, L, R;
vector <int> g[N], vr, mr;
bool dfs(int v){
if(used[v])
return 0;
vr.push_back(v);
used[v] = 1;
for(int to : g[v]){
if((to > R || to < L) && to <= n)
continue;
if(mt[to] == -1 || dfs(mt[to])){
mt[to] = v;
mt[v] = to;
return true;
}
}
return false;
}
bool check(){
if(mt[L] == -1)
return true;
while(!mr.empty()){
int v = mr.back();
for(int i = 0; i < vr.size(); i ++){
used[vr[i]] = 0;
}
if(!dfs(v)){
break;
}
mr.pop_back();
}
return mr.empty();
}
bool ok(){
for(int i = n + 1; i <= n + m; i ++){
if(mt[i] != -1){
mt[ mt[i] ] = -1;
mt[i] = -1;
}
}
for(int i = n + 1; i <= n + m; i ++){
for(int j = 0; j < (int)vr.size(); j ++){
used[ vr[j] ] = 0;
}
vr.clear();
dfs(i);
}
for(int i = n + 1; i <= n + m; i ++){
if(mt[i] == -1)
return false;
}
return true;
}
int main(){
scanf("%d %d %d", &n, &m, &k);
for(int i = 1; i <= k; i ++){
int a, b;
scanf("%d %d", &a, &b);
g[a].push_back(b + n);
g[b + n].push_back(a);
}
for(int i = 1; i <= n + m; i ++){
sort(g[i].begin(), g[i].end());
}
memset(mt, -1, sizeof(mt));
int lo = 1, hi = n, pos = -1;
L = 1;
while(hi - lo > 1){
int md = (lo + hi) >> 1;
R = md;
if(ok())
hi = md - 1, pos = md;
else
lo = md + 1;
}
if(pos == -1){
cout << 0 << endl;
return 0;
}
ans += n - pos + 1;
if(mt[L] != -1){
mt[mt[L]] = -1;
mr.push_back(mt[L]);
}
int pt = pos;
for(int i = 2; i <= n - m + 1; i ++){
int lo = 1, hi = i;
L = i, R = pt;
while(pt <= n && !check())
pt ++, R = pt;
ans += n - pt + 1;
if(mt[L] != -1){
mt[mt[L]] = -1;
mr.push_back(mt[L]);
}
}
printf("%d", ans);
}
Compilation message (stderr)
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