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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 |
---|---|---|---|---|---|---|---|---|---|
#86560 | #4231. Rafting Trip | cardinal_city# | TL | 8ms | 19552kb | C++20 | 3.1kb | 2023-03-10 08:15:37 | 2023-03-10 08:15:41 |
Judging History
answer
#include <bits/stdc++.h>
using namespace std;
set<int> bins;
int r,c;
int dr[4] = {0,0,1,-1};
int dc[4] = {1,-1,0,0};
map<char, int> dir = {{'>', 0}, {'<', 1}, {'v', 2}, {'^', 3}, {'.', -1}, {'#', -1}};
int inv[300000] = {};
vector<int> cycidx(300000, -1);
vector<int> nxt(300000, -1000000);
set<int> adjbins[300000];
vector<set<int>> cycbins;
int numcyc = 0;
int vis[300000] = {};
int ans = 0;
set<int> currbins;
int to_idx(int i, int j) {
return (c+2) * i + j;
}
void dfs(int u) {
if(vis[u] == 2) return;
if(vis[u] == 1) {
int v = nxt[u];
vector<int> cyc = {u};
while(v != u) {
cyc.push_back(v);
v = nxt[v];
}
set<int> cbins;
for(auto x : cyc) {
for(auto b : adjbins[x]) {
cbins.insert(b);
}
cycidx[x] = numcyc;
}
cycbins.push_back(cbins);
numcyc++;
return;
}
vis[u] = 1;
if(nxt[u] != -1000000) dfs(nxt[u]);
vis[u] = 2;
return;
}
void dfs2(int u) {
// cout << "U " << u << endl;
if(cycidx[u] != -1) {
// cout << u << " " << cycidx[u] << " " << cycbins.size() << endl;
for(int b : cycbins[cycidx[u]]) currbins.insert(b);
return;
}
if(nxt[u] != -1000000) {
for(int b : adjbins[u]) currbins.insert(b);
dfs2(nxt[u]);
}
}
int main() {
cin.tie(0)->sync_with_stdio(0);
cin >> r >> c;
char g[510][510] = {};
for(int i = 1; i <= r; i++) {
for(int j = 1; j <= c; j++) {
cin >> g[i][j];
if(g[i][j] == '#') bins.insert(to_idx(i,j));
}
}
for(int i = 1; i <= r; i++) {
for(int j = 1; j <= c; j++) {
int d = dir[g[i][j]];
int idx = to_idx(i,j);
if(d >= 0) {
int ni = i + dr[d];
int nj = j + dc[d];
int nidx = to_idx(ni, nj);
inv[nidx]++;
nxt[idx] = nidx;
for(int k = 0; k < 4; k++) {
int ki = i + dr[k];
int kj = j + dc[k];
int kidx = to_idx(ki, kj);
if(bins.count(kidx)) adjbins[idx].insert(kidx);
}
}
}
}
for(int i = 1; i <= r; i++) {
for(int j = 1; j <= c; j++) {
int idx = to_idx(i,j);
if(vis[idx] == 0 && nxt[idx] != -1000000) {
dfs(idx);
}
}
}
for(int i = 1; i <= r; i++) {
for(int j = 1; j <= c; j++) {
int idx = to_idx(i,j);
vis[idx] = 0;
}
}
for(int i = 1; i <= r; i++) {
for(int j = 1; j <= c; j++) {
int idx = to_idx(i,j);
if(inv[idx] == 0 && nxt[idx] != -1000000) {
currbins.clear();
dfs2(idx);
ans = max(ans, (int) currbins.size());
}
}
}
for(auto x : cycbins) {
ans = max(ans, (int) x.size());
}
cout << ans << endl;
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 4ms
memory: 19500kb
input:
5 6 v<<<#v v#v<.> >>v<<< ..v##^ #<<<.^
output:
4
result:
ok single line: '4'
Test #2:
score: 0
Accepted
time: 4ms
memory: 19460kb
input:
4 5 >v<<. ^<..# #...# .#>^#
output:
2
result:
ok single line: '2'
Test #3:
score: 0
Accepted
time: 6ms
memory: 19524kb
input:
4 6 >>v#>v ^#>>^v ^<<#v< .#^<<#
output:
5
result:
ok single line: '5'
Test #4:
score: 0
Accepted
time: 6ms
memory: 19492kb
input:
6 6 ^.>>>> ^..... ^....v ^....v #....v <<<<#v
output:
2
result:
ok single line: '2'
Test #5:
score: 0
Accepted
time: 4ms
memory: 19524kb
input:
6 7 ^>>>>>v ^.....v ^.#^..v ^.#^<.v ^.....v ^<<<<<<
output:
2
result:
ok single line: '2'
Test #6:
score: 0
Accepted
time: 4ms
memory: 19540kb
input:
3 7 >v<<<<# ^<##### #^<<<<<
output:
6
result:
ok single line: '6'
Test #7:
score: 0
Accepted
time: 7ms
memory: 19476kb
input:
3 5 ><.v# ##.^# ...#.
output:
3
result:
ok single line: '3'
Test #8:
score: 0
Accepted
time: 4ms
memory: 19548kb
input:
7 3 ### #># ### ... ### #>. ###
output:
4
result:
ok single line: '4'
Test #9:
score: 0
Accepted
time: 8ms
memory: 19548kb
input:
2 2 >. .#
output:
0
result:
ok single line: '0'
Test #10:
score: 0
Accepted
time: 4ms
memory: 19552kb
input:
2 2 .. .v
output:
0
result:
ok single line: '0'
Test #11:
score: -100
Time Limit Exceeded
input:
498 498 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<...