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| ##include "bits/stdc++.h"
using namespace std;
##define INF 0x3f3f3f3f
struct Dinic {
static const int N = 1e5 + 10, M = 2e5 + 10;
int n, m, s, t, maxflow;
int deep[N], cur[N];
struct Edge {
int v, next;
int cap;
}e[M << 1];
int head[M << 1], cnt;
void init() {
mem(head, -1);
cnt = maxflow = 0;
}
inline void add(int u, int v, int cap) {
e[cnt].v = v;
e[cnt].cap = cap;
e[cnt].next = head[u];
head[u] = cnt++;
e[cnt].v = u;
e[cnt].cap = 0;
e[cnt].next = head[v];
head[v] = cnt++;
}
bool bfs() {
for(int i = 0;i <= t; i++) {
deep[i] = -1; cur[i] = head[i];
}
queue<int> q;
q.push(s); deep[s] = 0;
while(!q.empty()) {
int u = q.front(); q.pop();
for(int i = head[u]; ~i; i = e[i].next) {
int v = e[i].v;
if(deep[v] == -1 && e[i].cap) {
deep[v] = deep[u] + 1;
q.push(v);
}
}
}
if(deep[t] >= 0) return true;
else return false;
}
int dfs(int u, int mx) {
int a;
if(u == t) return mx;
for(int i = cur[u]; ~i; i = e[i].next) {
cur[u] = i;
int v = e[i].v;
if(e[i].cap && deep[v] == deep[u] + 1 && (a = dfs(v, min(mx, e[i].cap)))) {
e[i].cap -= a;
e[i ^ 1].cap += a;
return a;
}
}
return 0;
}
void dinic() {
int res;
while(bfs()) {
while(1) {
res = dfs(s, INF);
if(!res) break;
maxflow += res;
}
}
}
}mf;
void solve() {
int _; cin >> _;
while(_--) {
mf.init();
int n; cin >> n;
vector<int> v1, v2;
vector<int> x(n), y(n);
for(int i = 0;i < n; i++) {
int a, b; cin >> a >> b;
x[i] = a + b; y[i] = a - b;
v1.push_back(x[i]);
v2.push_back(y[i]);
}
sort(v1.begin(), v1.end());
sort(v2.begin(), v2.end());
v1.erase(unique(v1.begin(), v1.end()), v1.end());
v2.erase(unique(v2.begin(), v2.end()), v2.end());
int len = v1.size();
mf.s = 0; mf.t = v1.size() + v2.size() + 1;
for(int i = 1;i <= len; i++) {
mf.add(mf.s, i, 1);
}
for(int i = len + 1;i <= mf.t - 1; i++) {
mf.add(i, mf.t, 1);
}
for(int i = 0;i < n; i++) {
int u = lower_bound(v1.begin(), v1.end(), x[i]) - v1.begin() + 1;
int v = lower_bound(v2.begin(), v2.end(), y[i]) - v2.begin() + 1;
mf.add(u, v + len, 1);
}
mf.dinic();
cout << mf.maxflow << endl;
}
}
signed main() {
solve();
}
|