Submission #6355185

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Source Code Expand

#include <map>
#include <cmath>
#include <string>
#include <cstdio>
#include <cstring>
#include <algorithm>
using std::map; using std::string;
using std::min; using std::max;
using std::swap; using std::sort;
typedef long long ll;

template<typename T>
void read(T &x) {
	int flag = 1; x = 0; char ch = getchar();
	while(ch < '0' || ch > '9') { if(ch == '-') flag = -flag; ch = getchar(); }
	while(ch >= '0' && ch <= '9') x = x * 10 + ch - '0', ch = getchar(); x *= flag;
}
#if __cplusplus >= 201103l
template<typename T, typename... V>
void read(T &x, V&... v) { read(x), read(v...); }
#endif

const int _ = 4e5 + 10;
int n, q, ff[_], d[_];
struct Edge { int u, v, w; } e[_]; int cnt;
inline bool operator < (const Edge &a, const Edge &b) { return a.w < b.w; }
inline void addEdge(int u, int v, int w) { e[++cnt] = {u, v, w}; }
void ChkMin(int &a, int b) { if(b < a) a = b; }
int find(int x) { return ff[x] == x ? x : ff[x] = find(ff[x]); }

int main () {
	read(n, q), memset(d, 127, sizeof(d[0]) * n);
	for(int i = 1, x, y, z; i <= q; ++i)
		read(x, y, z), addEdge(x, y, z), ChkMin(d[x], z + 1), ChkMin(d[y], z + 2);
	for(int i = 0; i < n; ++i) ChkMin(d[i], d[(i + n - 1) % n] + 2);
	for(int i = 0; i < n; ++i) ChkMin(d[i], d[(i + n - 1) % n] + 2);
	for(int i = 0; i < n; ++i) addEdge(i, (i + 1) % n, d[i]), ff[i] = i;
	sort(e + 1, e + cnt + 1); int blo = n; ll MST = 0;
	for(int i = 1; i <= cnt && blo > 1; ++i) {
		int u = find(e[i].u), v = find(e[i].v);
		if(u == v) continue; ff[u] = v, MST += e[i].w, --blo;
	}
	printf("%lld\n", MST);
	return 0;
} 

Submission Info

Judge Result