hdu 5361 In Touch（最短路+并查集）

题目链接：hdu 5361 In Touch

最短路，D[i]表示从i节点出发时最短距离，最后答案减掉C[i]即可。然后用并查集优化维护处理过的节点。

#pragma comment(linker, "/STACK:102400000,102400000")
#include <cstdio>
#include <cstring>
#include <queue>
#include <algorithm>

using namespace std;
typedef long long ll;
const int maxn = 2 * 1e5 + 5;
const ll inf = 1LL << 60;

struct Pi {
int pos;
ll dis;
Pi (int pos = 0, ll dis = 0): pos(pos), dis(dis) {}
bool operator < (const Pi& u) const {
return dis > u.dis;
}
};

int N, L[maxn], R[maxn], C[maxn], F[maxn];
ll D[maxn];

int find (int x) {
return F[x] = (F[x] == x ? x : find(F[x]));
}

void init () {
scanf("%d", &N);
for (int i = 1; i <= N; i++) {
F[i] = i;
D[i] = inf;
}
for (int i = 1; i <= N; i++)
scanf("%d", &L[i]);
for (int i = 1; i <= N; i++)
scanf("%d", &R[i]);
for (int i = 1; i <= N; i++)
scanf("%d", &C[i]);
}

void solve (int s) {
D[s] = C[s];
priority_queue<Pi> Q;
Q.push(Pi(s, D[s]));

while (!Q.empty()) {
int u = Q.top().pos;
Q.pop();

for (int i = -1; i <= 1; i += 2) {
int lp = u + L[u] * i;
int rp = u + R[u] * i;
if (lp > rp)
swap(lp, rp);

lp = max(lp, 1);
lp = min(lp, N + 1);

if (lp > rp)
continue;

while (true) {
lp = find(lp);
if (lp <= 0 || lp > N || lp > rp)
break;
if (D[lp] > D[u] + C[lp]) {
D[lp] = D[u] + C[lp];
Q.push(Pi(lp, D[lp]));
}
F[find(lp)] = find(lp + 1);
lp++;
}
}
}

printf("0");
for (int i = 2; i <= N; i++)
printf(" %I64d", D[i] == inf ? -1 : D[i] - C[i]);
printf("\n");
}

int main () {
int cas;
scanf("%d", &cas);
while (cas--) {
init();
solve(1);
}
return 0;
}