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Algorithm — Stable matching problem implementation using c++
The Stable Marriage Problem and School Choice
Stable Marriage Problem
স্টেবল ম্যারেজ প্রবলেম
Shakil Ahmed's video
Implementation:
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//https://www.codechef.com/problems/STABLEMP | |
#include <bits/stdc++.h> | |
using namespace std; | |
#define INF 1<<30 | |
#define endl '\n' | |
#define maxn 1000005 | |
#define FASTIO ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0); | |
typedef long long ll; | |
const double PI = acos(-1.0); | |
const ll mod = 1e9 + 7; | |
inline void normal(ll &a) { a %= mod; (a < 0) && (a += mod); } | |
inline ll modMul(ll a, ll b) { a %= mod, b %= mod; normal(a), normal(b); return (a * b) % mod; } | |
inline ll modAdd(ll a, ll b) { a %= mod, b %= mod; normal(a), normal(b); return (a + b) % mod; } | |
inline ll modSub(ll a, ll b) { a %= mod, b %= mod; normal(a), normal(b); a -= b; normal(a); return a; } | |
inline ll modPow(ll b, ll p) { ll r = 1; while (p) { if (p & 1) r = modMul(r, b); b = modMul(b, b); p >>= 1; } return r; } | |
inline ll modInverse(ll a) { return modPow(a, mod - 2); } | |
inline ll modDiv(ll a, ll b) { return modMul(a, modInverse(b)); } | |
///** | |
template < typename F, typename S > | |
ostream& operator << ( ostream& os, const pair< F, S > & p ) { | |
return os << "(" << p.first << ", " << p.second << ")"; | |
} | |
template < typename T > | |
ostream &operator << ( ostream & os, const vector< T > &v ) { | |
os << "{"; | |
for (auto it = v.begin(); it != v.end(); ++it) { | |
if ( it != v.begin() ) os << ", "; | |
os << *it; | |
} | |
return os << "}"; | |
} | |
template < typename T > | |
ostream &operator << ( ostream & os, const set< T > &v ) { | |
os << "["; | |
for (auto it = v.begin(); it != v.end(); ++it) { | |
if ( it != v.begin()) os << ", "; | |
os << *it; | |
} | |
return os << "]"; | |
} | |
template < typename F, typename S > | |
ostream &operator << ( ostream & os, const map< F, S > &v ) { | |
os << "["; | |
for (auto it = v.begin(); it != v.end(); ++it) { | |
if ( it != v.begin() ) os << ", "; | |
os << it -> first << " = " << it -> second ; | |
} | |
return os << "]"; | |
} | |
#define dbg(args...) do {cerr << #args << " : "; faltu(args); } while(0) | |
clock_t tStart = clock(); | |
#define timeStamp dbg("Execution Time: ", (double)(clock() - tStart)/CLOCKS_PER_SEC) | |
void faltu () { cerr << endl; } | |
template <typename T> | |
void faltu( T a[], int n ) { | |
for (int i = 0; i < n; ++i) cerr << a[i] << ' '; | |
cerr << endl; | |
} | |
template <typename T, typename ... hello> | |
void faltu( T arg, const hello &... rest) { cerr << arg << ' '; faltu(rest...); } | |
// Program showing a policy-based data structure. | |
#include <ext/pb_ds/assoc_container.hpp> // Common file | |
#include <ext/pb_ds/tree_policy.hpp> | |
#include <functional> // for less | |
#include <iostream> | |
using namespace __gnu_pbds; | |
using namespace std; | |
// GNU link : https://goo.gl/WVDL6g | |
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, | |
tree_order_statistics_node_update> | |
new_data_set; | |
// find_by_order(k) – ফাংশনটি kth ordered element এর একটা পয়েন্টার রিটার্ন করে। অর্থাৎ তুমি চাইলেই kth ইন্ডেক্সে কি আছে, সেটা জেনে ফেলতে পারছো! | |
// order_of_key(x) – ফাংশনটি x এলিমেন্টটা কোন পজিশনে আছে সেটা বলে দেয়। | |
//*//**___________________________________________________**/ | |
vector<int> stableMariage(const vector<vector<int> > &menPf, const vector<vector<int> > &womenPf) | |
{ | |
const int N = menPf.size(); | |
vector<vector<int>> mapWomenToMan(N); | |
for (int i = 0; i < N; i++) mapWomenToMan[i].resize(N); | |
for (int i = 0; i < N; i++) | |
for (int j = 0; j < N; j++) | |
mapWomenToMan[i][womenPf[i][j]] = j; | |
vector<int> womenMatch(N, -1); | |
vector<int> manMatch(N, -1); | |
queue<int> bachelors; | |
for (int i = 0; i < N; i++) bachelors.push(i); | |
while (!bachelors.empty()) { | |
int man = bachelors.front(); | |
bachelors.pop(); | |
for (int woman : menPf[man]) { | |
if (womenMatch[woman] == -1) { /// women is free | |
womenMatch[woman] = man; | |
manMatch[man] = woman; | |
break; | |
} | |
else { | |
int otherMan = womenMatch[woman]; | |
if (mapWomenToMan[woman][otherMan] > mapWomenToMan[woman][man]) { | |
manMatch[otherMan] = -1;// free the other man | |
bachelors.push(otherMan); | |
womenMatch[woman] = man; | |
manMatch[man] = woman; | |
break; | |
} | |
} | |
} | |
} | |
return manMatch; | |
} | |
int main() | |
{ | |
//FASTIO | |
///* | |
#ifndef ONLINE_JUDGE | |
freopen("in.txt", "r", stdin); | |
freopen("out.txt", "w", stdout); | |
freopen("error.txt", "w", stderr); | |
#endif | |
//*/ | |
int T; | |
scanf("%d", &T); | |
//T = 1; | |
for (int cs = 1; cs <= T; cs++) { | |
int n; scanf("%d", &n); | |
vector<vector<int> > menPf(n), womenPf(n); | |
for (int i = 0; i < n; i++) { | |
womenPf[i].resize(n); | |
int x; | |
scanf("%d", &x); | |
for (int j = 0; j < n; j++) { | |
scanf("%d", &womenPf[i][j]); | |
womenPf[i][j]--; | |
} | |
} | |
for (int i = 0; i < n; i++) { | |
menPf[i].resize(n); | |
int x; | |
scanf("%d", &x); | |
for (int j = 0; j < n; j++) { | |
scanf("%d", &menPf[i][j]); | |
menPf[i][j]--; | |
} | |
} | |
vector<int> marriages = stableMariage(menPf, womenPf); | |
for (int i = 0; i < n; i++) { | |
printf("%d %d\n", i + 1, marriages[i] + 1); | |
} | |
} | |
return 0; | |
} |
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// 2nd solution | |
#include <bits/stdc++.h> | |
using namespace std; | |
#define INF 1<<30 | |
#define endl '\n' | |
#define maxn 1000005 | |
#define FASTIO ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0); | |
typedef long long ll; | |
const double PI = acos(-1.0); | |
const ll mod = 1e9 + 7; | |
inline void normal(ll &a) { a %= mod; (a < 0) && (a += mod); } | |
inline ll modMul(ll a, ll b) { a %= mod, b %= mod; normal(a), normal(b); return (a * b) % mod; } | |
inline ll modAdd(ll a, ll b) { a %= mod, b %= mod; normal(a), normal(b); return (a + b) % mod; } | |
inline ll modSub(ll a, ll b) { a %= mod, b %= mod; normal(a), normal(b); a -= b; normal(a); return a; } | |
inline ll modPow(ll b, ll p) { ll r = 1; while (p) { if (p & 1) r = modMul(r, b); b = modMul(b, b); p >>= 1; } return r; } | |
inline ll modInverse(ll a) { return modPow(a, mod - 2); } | |
inline ll modDiv(ll a, ll b) { return modMul(a, modInverse(b)); } | |
///** | |
template < typename F, typename S > | |
ostream& operator << ( ostream& os, const pair< F, S > & p ) { | |
return os << "(" << p.first << ", " << p.second << ")"; | |
} | |
template < typename T > | |
ostream &operator << ( ostream & os, const vector< T > &v ) { | |
os << "{"; | |
for (auto it = v.begin(); it != v.end(); ++it) { | |
if ( it != v.begin() ) os << ", "; | |
os << *it; | |
} | |
return os << "}"; | |
} | |
template < typename T > | |
ostream &operator << ( ostream & os, const set< T > &v ) { | |
os << "["; | |
for (auto it = v.begin(); it != v.end(); ++it) { | |
if ( it != v.begin()) os << ", "; | |
os << *it; | |
} | |
return os << "]"; | |
} | |
template < typename F, typename S > | |
ostream &operator << ( ostream & os, const map< F, S > &v ) { | |
os << "["; | |
for (auto it = v.begin(); it != v.end(); ++it) { | |
if ( it != v.begin() ) os << ", "; | |
os << it -> first << " = " << it -> second ; | |
} | |
return os << "]"; | |
} | |
#define dbg(args...) do {cerr << #args << " : "; faltu(args); } while(0) | |
clock_t tStart = clock(); | |
#define timeStamp dbg("Execution Time: ", (double)(clock() - tStart)/CLOCKS_PER_SEC) | |
void faltu () { cerr << endl; } | |
template <typename T> | |
void faltu( T a[], int n ) { | |
for (int i = 0; i < n; ++i) cerr << a[i] << ' '; | |
cerr << endl; | |
} | |
template <typename T, typename ... hello> | |
void faltu( T arg, const hello &... rest) { cerr << arg << ' '; faltu(rest...); } | |
// Program showing a policy-based data structure. | |
#include <ext/pb_ds/assoc_container.hpp> // Common file | |
#include <ext/pb_ds/tree_policy.hpp> | |
#include <functional> // for less | |
#include <iostream> | |
using namespace __gnu_pbds; | |
using namespace std; | |
// GNU link : https://goo.gl/WVDL6g | |
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, | |
tree_order_statistics_node_update> | |
new_data_set; | |
// find_by_order(k) – ফাংশনটি kth ordered element এর একটা পয়েন্টার রিটার্ন করে। অর্থাৎ তুমি চাইলেই kth ইন্ডেক্সে কি আছে, সেটা জেনে ফেলতে পারছো! | |
// order_of_key(x) – ফাংশনটি x এলিমেন্টটা কোন পজিশনে আছে সেটা বলে দেয়। | |
//*//**___________________________________________________**/ | |
const int N = 505; | |
int pw[N][N], pm[N][N]; | |
int cw[N], cm[N]; | |
void find_wife(int p) | |
{ | |
if (p == 0) return; | |
cm[p]++; | |
while (1) { | |
int w = pm[p][cm[p]]; | |
if (cw[w] == 0 || pw[w][p] < pw[w][cw[w]]) { | |
int h = cw[w]; | |
cw[w] = p; | |
find_wife(h); | |
return; | |
} | |
cm[p]++; | |
} | |
} | |
int main() | |
{ | |
//FASTIO | |
///* | |
#ifndef ONLINE_JUDGE | |
freopen("in.txt", "r", stdin); | |
freopen("out.txt", "w", stdout); | |
freopen("error.txt", "w", stderr); | |
#endif | |
//*/ | |
int T; | |
scanf("%d", &T); | |
//T = 1; | |
for (int cs = 1; cs <= T; cs++) { | |
int n; | |
scanf("%d", &n); | |
memset(pw, 0, sizeof pw); | |
memset(pm, 0, sizeof pm); | |
memset(cw, 0, sizeof cw); | |
memset(cm, 0, sizeof cm); | |
for (int i = 1; i <= n; i++) { | |
int p; | |
scanf("%d", &p); | |
for (int j = 1; j <= n; j++) { | |
int x; | |
scanf("%d", &x); | |
pw[p][x] = j; | |
} | |
} | |
for (int i = 1; i <= n; i++) { | |
int p; | |
scanf("%d", &p); | |
for (int j = 1; j <= n; j++) { | |
int x; | |
scanf("%d", &x); | |
pm[p][j] = x; | |
} | |
find_wife(p); | |
} | |
for (int i = 1; i <= n; i++) { | |
//cout << i << " " << pm[i][cm[i]] << "\n"; | |
printf("%d %d\n", i, pm[i][cm[i]]); | |
} | |
} | |
return 0; | |
} |
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