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QOJ
ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#870171 | #4809. Maximum Range | XuYueming | WA | 22ms | 12204kb | C++20 | 9.4kb | 2025-01-25 15:06:50 | 2025-01-25 15:06:50 |
Judging History
answer
#include <cstdio>
#include <iostream>
#include <vector>
#include <cstring>
#include <cassert>
#include <algorithm>
#include <queue>
using namespace std;
const int N = 100010, M = 100010;
struct node {
int to, nxt, len;
} edge[M << 1];
int head[N], tot = 1;
void add(int u, int v, int w) {
edge[++tot] = {
.to = v, .nxt = head[u], .len = w
}, head[u] = tot;
}
int n, m;
int dfn[N], low[N], timer;
int stack[N], top;
int scnt, sccno[N];
void tarjan(int u, int f) {
dfn[u] = low[u] = ++timer;
stack[++top] = u;
for (int i = head[u]; i; i = edge[i].nxt) {
if ((i ^ f) == 1) continue;
int v = edge[i].to;
if (!dfn[v]) {
tarjan(v, i);
low[u] = min(low[u], low[v]);
} else {
low[u] = min(low[u], dfn[v]);
}
}
if (low[u] == dfn[u]) {
++scnt;
do {
int v = stack[top--];
sccno[v] = scnt;
// printf("%d: %d\n", scnt, v);
} while (stack[top + 1] != u);
}
}
int mx[N], mi[N], xp[N], ip[N];
// bool ins[N << 1], vis[N];
// bool dfs(int u, int fr, vector<int>& vec, int target) {
// vis[u] = true;
// if (u == target) return vec.emplace_back(u), true;
// for (int i = head[u]; i; i = edge[i].nxt) {
// if (i == (fr ^ 1)) continue;
// if (ins[i]) continue;
// int v = edge[i].to;
// if (vis[v]) continue;
// bool res = dfs(v, i, vec, target);
// if (res) {
// ins[i] = ins[i ^ 1] = true;
// vec.emplace_back(u);
// return true;
// }
// }
// return false;
// }
vector<int> ans;
int xxx, iii, u1, u2, v1, v2;
// bool intree[M << 1], vis[N];
// int FA[N], DOWN;
// void dfs(int u, int fr) {
// vis[u] = true;
// if (u == v1) FA[u1] = u, dfs(u1, xxx);
// if (u == u2 && fr != iii) FA[v2] = u, DOWN = v2, dfs(v2, iii ^ 1);
// if (u == v2 && fr != (iii ^ 1)) FA[u2] = u, DOWN = u2, dfs(u2, iii);
// for (int i = head[u]; i; i = edge[i].nxt) {
// if (i == (fr ^ 1)) continue;
// if (i == (xxx ^ 1)) continue;
// if (i == iii) continue;
// if (i == (iii ^ 1)) continue;
// int v = edge[i].to;
// if (vis[v]) continue;
// FA[v] = u;
// intree[i] = intree[i ^ 1] = true;
// dfs(v, i);
// }
// }
// bool can[N];
// int fff[N];
// bool dfs(int u) {
// if (can[u]) {
// // printf("fff[5] = %d\n", fff[5]);
// // printf("fff[4] = %d\n", fff[4]);
// for (int x = u; x; x = fff[x])
// ans.emplace_back(x);
// reverse(ans.begin(), ans.end());
// return true;
// }
// for (int i = head[u]; i; i = edge[i].nxt) {
// if (!intree[i]) continue;
// int v = edge[i].to;
// if (v == FA[u]) continue;
// bool rr = dfs(v);
// if (rr) {
// ans.emplace_back(u);
// return true;
// }
// }
// return false;
// }
struct Net_Max_Flow {
struct Graph {
struct node {
int to, flow, cap, nxt;
} edge[M << 3];
int tot = 1, head[N];
inline void add(int u, int v, int w) {
edge[++tot] = {v, 0, w, head[u]};
head[u] = tot;
}
inline node & operator [] (const int x) {
return edge[x];
}
} xym;
int n;
inline void init(int _n) {
n = _n, xym.tot = 1;
memset(xym.head + 1, 0x00, sizeof (int) * n);
}
inline void add(int u, int v, int fl, bool tag = false) {
if (!tag) xym.add(u, v, fl), xym.add(v, u, 0);
else {
xym.add(u, v, fl), xym.add(v, u, fl);
}
}
bool vis[N];
int flow(int u, int T, int lim) {
if (u == T) return lim;
vis[u] = true;
for (int i = xym.head[u]; i; i = xym.edge[i].nxt)
if (xym.edge[i].flow < xym.edge[i].cap) {
int v = xym.edge[i].to;
if (!vis[v] && flow(v, T, lim))
return ++xym.edge[i].flow, --xym.edge[i ^ 1].flow, 1;
}
return 0;
}
long long solve(int S, int T) {
long long flow = 0;
for (int _ = 1; _ <= 2; ++_) {
memset(vis, 0x00, sizeof(vis));
assert(this -> flow(S, T, 1) == 1);
}
return flow = 2;
}
} yzh;
signed main() {
scanf("%d%d", &n, &m);
for (int i = 1, u, v, w; i <= m; ++i) {
scanf("%d%d%d", &u, &v, &w);
add(u, v, w), add(v, u, w);
}
for (int i = 1; i <= n; ++i)
if (!dfn[i])
tarjan(i, 0);
for (int i = 1; i <= scnt; ++i) {
mx[i] = -0x3f3f3f3f;
mi[i] = 0x3f3f3f3f;
}
for (int u = 1; u <= n; ++u)
for (int i = head[u]; i; i = edge[i].nxt) {
int v = edge[i].to;
if (sccno[v] != sccno[u]) continue;
int w = edge[i].len;
// printf("====== %d\n", w);
int x = sccno[u];
if (w > mx[x])
mx[x] = w, xp[x] = i;
if (w < mi[x])
mi[x] = w, ip[x] = i;
}
int mm = 0, idx = -1;
for (int i = 1; i <= scnt; ++i)
if (mx[i] - mi[i] > mm) {
mm = mx[i] - mi[i];
idx = i;
}
printf("%d\n", mm);
int X = xp[idx], I = ip[idx];
u1 = edge[X].to, v1 = edge[X ^ 1].to;
u2 = edge[I].to, v2 = edge[I ^ 1].to;
if (u1 == v2) swap(u2, v2), I ^= 1;
if (v1 == u2) swap(u1, v1), X ^= 1;
if (v1 == v2) swap(u2, v2), I ^= 1, swap(u1, v1), X ^= 1;
fprintf(stderr, "(%d, %d): %d\n", u1, v1, edge[X].len);
fprintf(stderr, "(%d, %d): %d\n", u2, v2, edge[I].len);
iii = I, xxx = X;
int III = n + 1, XXX = n + 2;
yzh.init(n + 2);
yzh.add(III, u1, 1);
yzh.add(III, v1, 1);
yzh.add(u2, XXX, 1);
yzh.add(v2, XXX, 1);
for (int u = 1; u <= n; ++u)
if (sccno[u] == idx)
for (int i = head[u]; i; i = edge[i].nxt) {
int v = edge[i].to;
if (sccno[v] != idx) continue;
if (v > u) continue;
if (u == u1 && v == v1) continue;
if (u == v1 && v == u1) continue;
if (u == u2 && v == v2) continue;
if (u == v2 && v == u2) continue;
// puts("dfsdfsdfsdfsdfs");
// yzh.add(u, v, 1);
yzh.add(v, u, 1, true);
}
int res = yzh.solve(III, XXX);
fprintf(stderr, "maxflow = %d\n", res);
assert(res == 2);
int TTTTTTTT = 0;
for (int u = u1; u != XXX; ) {
ans.push_back(u);
for (int i = yzh.xym.head[u]; i; i = yzh.xym.edge[i].nxt) {
int v = yzh.xym.edge[i].to;
if (yzh.xym.edge[i].flow != 1) continue;
if (v == III) continue;
if (v == XXX) {
TTTTTTTT = u2 ^ v2 ^ u;
}
u = v;
break;
}
}
vector<int> tmp;
for (int u = TTTTTTTT; u != III; ) {
// printf("u = %d\n", u);
tmp.push_back(u);
for (int i = yzh.xym.head[u]; i; i = yzh.xym.edge[i].nxt) {
int v = yzh.xym.edge[i].to;
if (yzh.xym.edge[i ^ 1].flow != 1) continue;
if (v == XXX) continue;
u = v;
break;
}
}
// reverse(tmp.begin(), tmp.end());
for (int x : tmp) ans.push_back(x);
// intree[X] = intree[X ^ 1] = true;
// intree[I] = intree[I ^ 1] = true;
// dfs(v1, 0);
// // for (int u = 1; u <= n; ++u)
// // printf(">>> %d %d\n", u, FA[u]);
// queue<int> Q;
// Q.push(v1), can[v1] = true;
// while (!Q.empty()) {
// int u = Q.front(); Q.pop();
// for (int i = head[u]; i; i = edge[i].nxt) {
// if (!intree[i]) continue;
// int v = edge[i].to;
// if (v == FA[u]) continue;
// Q.push(v);
// }
// if (can[u]) {
// for (int i = head[u]; i; i = edge[i].nxt) {
// if (intree[i]) continue;
// int v = edge[i].to;
// if (can[v]) continue;
// can[v] = true;
// fff[v] = u;
// }
// }
// }
// // printf("DOWN = %d\n", DOWN);
// bool rerrr = dfs(DOWN);
// assert(rerrr);
// for (int x = FA[DOWN]; FA[x]; x = FA[x])
// ans.emplace_back(x);
// assert(can[DOWN]);
printf("%d\n", int(ans.size()));
for (int x : ans) printf("%d ", x);
// vector<int> vec1, vec2;
// ins[X] = ins[X ^ 1] = true;
// ins[I] = ins[I ^ 1] = true;
// bool res1 = dfs(u1, 0, vec1, u2);
// assert(res1);
// memset(vis, 0x00, sizeof(vis));
// bool res2 = dfs(v2, 0, vec2, v1);
// if (!res2) {
// swap(u2, v2);
// fprintf(stderr, "(%d, %d): %d\n", u1, v1, edge[X].len);
// fprintf(stderr, "(%d, %d): %d\n", u2, v2, edge[I].len);
// vec1.clear();
// memset(vis, 0x00, sizeof(vis));
// memset(ins, 0x00, sizeof(ins));
// ins[X] = ins[X ^ 1] = true;
// ins[I] = ins[I ^ 1] = true;
// res1 = dfs(u1, 0, vec1, u2);
// assert(res1);
// memset(vis, 0x00, sizeof(vis));
// res2 = dfs(v2, 0, vec2, v1);
// assert(res2);
// }
// printf("%d\n", int(vec1.size() + vec2.size()));
// // assert(res2);
// for (int x : vec2) printf("%d ", x);
// for (int x : vec1) printf("%d ", x);
// // puts("");
// // reverse(vec2.begin(), vec2.end());
return 0;
}
Details
Tip: Click on the bar to expand more detailed information
Test #1:
score: 100
Accepted
time: 0ms
memory: 8012kb
input:
5 7 1 2 1 1 3 -2 2 3 1 3 4 3 4 5 1 1 5 -1 2 5 2
output:
5 4 3 1 5 4
result:
ok ok
Test #2:
score: 0
Accepted
time: 22ms
memory: 10696kb
input:
99997 100000 12238 99016 352755196 99016 25485 -412473602 25485 2440 991507552 2440 31171 -181894654 36970 2440 -800167579 2440 41865 -148191946 96629 31171 847888506 36970 95740 395546542 27992 2440 647886610 99016 29557 369124914 80795 27992 -673871966 36970 3509 573208857 57672 29557 874406776 41...
output:
1959330954 56 96048 4697 44442 68883 69259 57672 29557 99016 25485 73944 10503 93639 43423 7822 22393 79804 21467 41262 37318 80875 964 80256 57732 56899 24616 94522 90367 27992 2440 31171 95092 34883 46301 96778 37694 88289 30288 68523 54073 84997 89628 67966 84407 3463 72825 51491 87712 96230 2207...
result:
ok ok
Test #3:
score: 0
Accepted
time: 21ms
memory: 10568kb
input:
99997 100000 41884 21178 -431811360 41884 42699 -450057006 36523 21178 582079730 21178 96679 615552614 63637 21178 498974417 96679 5108 235820276 75058 41884 220112636 35148 42699 589595309 36523 18002 -637739861 65854 5108 -312755792 45137 41884 -511118771 5108 31311 554050951 25335 35148 -28341059...
output:
1968439328 40 98098 99686 71024 89860 18331 78274 35287 14678 59612 54901 26981 83047 87303 41126 28694 6204 50088 5108 7577 69337 51434 52252 25926 90144 26071 33264 70298 99716 98733 71151 55330 83919 83711 38202 85192 45137 41884 42699 87673 23692
result:
ok ok
Test #4:
score: -100
Wrong Answer
time: 20ms
memory: 12204kb
input:
99984 99999 33974 29867 335681778 33974 87468 348956829 83048 87468 320849805 29867 69456 -424530698 72457 69456 -950650074 53838 83048 755969166 85914 69456 569454441 51728 87468 -202158773 15970 29867 -865071002 15970 94894 697607001 94894 74694 616318126 33974 11496 -89287579 53838 34365 -6577379...
output:
1985932414 95 80694 78849 28078 91542 83656 97838 70238 5449 75902 51728 87468 83048 53838 99503 39863 14477 96407 37891 95578 37766 93343 43068 834 53261 74033 70104 67164 18619 15809 27495 53416 39906 68004 89447 91521 47303 29675 2715 26901 15891 40356 94629 33513 14218 53663 48757 81135 48441 16...
result:
wrong answer Cycle contains repeated edge 53838-83048