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QOJ
ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#496511 | #4231. Rafting Trip | CelestialCoder# | TL | 2ms | 9764kb | C++20 | 3.6kb | 2024-07-28 12:26:29 | 2024-07-28 12:26:29 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
int r, c;
int arr[501][501];
int dx[] = {0, 1, 0, -1};
int dy[] = {1, 0, -1, 0};
vector<int> adj[300001];
int graph[300001];
vector<int> rev[300001];
int sid;
int visited[300001];
int cycle[300001];
int cid;
vector<int> ci[300001];
int init_dfs(int current) {
visited[current] = 1;
int next = graph[current];
if (cycle[next]) {
visited[current] = -1;
return -1;
}
if (visited[next] == 1) {
cycle[current] = ++cid;
ci[cid].push_back(current);
visited[current] = -1;
return current != next ? next : -1;
}
int r = init_dfs(next);
visited[current] = -1;
if (r == -1)
return -1;
ci[cid].push_back(current);
cycle[current] = cid;
if (current == r)
return -1;
return r;
}
int in_cnt;
int in[300001];
void push_adj(int idx) {
for (int i: adj[idx]) {
in_cnt += !in[i]++;
}
}
void pop_adj(int idx) {
for (int i: adj[idx]) {
in_cnt -= !--in[i];
}
}
int dfs(int current) {
push_adj(current);
int ret = in_cnt;
int size = rev[current].size();
for (int i = 0; i < size; ++i) {
int next = rev[current][i];
if (cycle[next])
continue;
ret = max(ret, dfs(next));
}
pop_adj(current);
return ret;
}
int track(int idx) {
int size = ci[idx].size();
for (int i = 0; i < size; ++i) {
int p = ci[idx][i];
push_adj(p);
}
int ret = in_cnt;
for (int i = 0; i < size; ++i) {
ret = max(ret, dfs(ci[idx][i]));
}
for (int i = 0; i < size; ++i) {
int p = ci[idx][i];
pop_adj(p);
}
return ret;
}
int main() {
cin >> r >> c;
sid = 4;
for (int i = 1; i <= r; ++i) {
for (int j = 1; j <= c; ++j) {
char v;
cin >> v;
if (v == '<')
arr[i][j] = 2;
else if (v == '>')
arr[i][j] = 0;
else if (v == '^')
arr[i][j] = 3;
else if (v == 'v')
arr[i][j] = 1;
else if (v == '.')
arr[i][j] = -1;
else
arr[i][j] = ++sid;
}
}
for (int i = 1; i <= r; ++i) {
for (int j = 1; j <= c; ++j) {
for (int k = 0; k < 4; ++k) {
int nx = i + dx[k], ny = j + dy[k];
if (nx <= 0 || ny <= 0 || nx > r || ny > c)
continue;
if (arr[nx][ny] >= 4) {
adj[i * c + j].push_back(arr[nx][ny]);
}
}
if (arr[i][j] >= 0 && arr[i][j] < 4) {
int nx = i + dx[arr[i][j]], ny = j + dy[arr[i][j]];
if (nx <= 0 || ny <= 0 || nx > r || ny > c ||
arr[nx][ny] < 0 || arr[nx][ny] >= 4) {
graph[i * c + j] = (0);
rev[0].push_back(i * c + j);
}
else {
graph[i * c + j] = (nx * c + ny);
rev[nx * c + ny].push_back(i * c + j);
}
}
}
}
for (int i = 1; i <= r; ++i) {
for (int j = 1; j <= c; ++j) {
if (arr[i][j] >= 0 && arr[i][j] < 4) {
if (!visited[i * c + j])
init_dfs(i * c + j);
}
}
}
int ans = 0;
for (int i = 1; i <= cid; ++i) {
ans = max(ans, track(i));
}
cout << ans;
}
详细
Test #1:
score: 100
Accepted
time: 2ms
memory: 7804kb
input:
5 6 v<<<#v v#v<.> >>v<<< ..v##^ #<<<.^
output:
4
result:
ok single line: '4'
Test #2:
score: 0
Accepted
time: 2ms
memory: 9756kb
input:
4 5 >v<<. ^<..# #...# .#>^#
output:
2
result:
ok single line: '2'
Test #3:
score: 0
Accepted
time: 2ms
memory: 9764kb
input:
4 6 >>v#>v ^#>>^v ^<<#v< .#^<<#
output:
5
result:
ok single line: '5'
Test #4:
score: 0
Accepted
time: 0ms
memory: 7752kb
input:
6 6 ^.>>>> ^..... ^....v ^....v #....v <<<<#v
output:
2
result:
ok single line: '2'
Test #5:
score: 0
Accepted
time: 0ms
memory: 9756kb
input:
6 7 ^>>>>>v ^.....v ^.#^..v ^.#^<.v ^.....v ^<<<<<<
output:
2
result:
ok single line: '2'
Test #6:
score: 0
Accepted
time: 0ms
memory: 7704kb
input:
3 7 >v<<<<# ^<##### #^<<<<<
output:
6
result:
ok single line: '6'
Test #7:
score: 0
Accepted
time: 2ms
memory: 9724kb
input:
3 5 ><.v# ##.^# ...#.
output:
3
result:
ok single line: '3'
Test #8:
score: 0
Accepted
time: 2ms
memory: 9724kb
input:
7 3 ### #># ### ... ### #>. ###
output:
4
result:
ok single line: '4'
Test #9:
score: 0
Accepted
time: 2ms
memory: 9660kb
input:
2 2 >. .#
output:
0
result:
ok single line: '0'
Test #10:
score: 0
Accepted
time: 1ms
memory: 7612kb
input:
2 2 .. .v
output:
0
result:
ok single line: '0'
Test #11:
score: -100
Time Limit Exceeded
input:
498 498 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<...