#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef long long ll;
typedef pair<ll,ll> pll;
typedef tuple<int,int,int> ti;
typedef unsigned long long ull;
typedef long double ld;
typedef vector<ll> vll;
typedef pair<ld,ld> pld;
#define pb push_back
#define popb pop_back()
#define pf push_front
#define popf pop_front
#define ff first
#define ss second
#define MOD (int)(1e9 + 7)
#define INF (ll) (1e18)
#define all(v) (v).begin(),(v).end()
ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;}
ll lcm(ll a , ll b) {return (a * b) / gcd(a , b);}
ld pointdist(ld x, ld y, ld point) { return ((x-point)*(y-point))/abs(x-y); }
//ld dist(ld x, ld y, ld a, ld b){ return sqrt((x-a)*(x-a) + (y-b)*(y-b)); }
const int nx[4] = {0, 0, 1, -1}, ny[4] = {1, -1, 0, 0}; //East, West, South, North+
////////////******SOLUTION******\\\\\\\\\\\
const int MAX_R = 1004;
char mat[MAX_R][MAX_R];
int r, c;
pii start;
pii arv;
int dist[MAX_R][MAX_R];
int near[MAX_R][MAX_R];
int psa[4][MAX_R][MAX_R];
void build()
{
int sof = 1;
for(int i = 0; i < r; i ++)
{
sof = 1;
for(int j = 0; j < c; j ++)
{
if(mat[i][j] == '#')
sof = 0;
psa[0][i][j] = sof;
sof ++;
}
}
for(int i = 0; i < r; i ++)
{
sof = 1;
for(int j = c-1; j >= 0; j --)
{
if(mat[i][j] == '#')
sof = 0;
psa[1][i][j] = sof;
sof ++;
}
}
for(int j = 0; j < c; j ++)
{
sof = 1;
for(int i = 0; i < r; i ++)
{
if(mat[i][j] == '#')
sof = 0;
psa[2][i][j] = sof;
sof ++;
}
}
for(int j = 0; j < c; j ++)
{
sof = 1;
for(int i = r-1; i >= 0; i --)
{
if(mat[i][j] == '#')
sof = 0;
psa[3][i][j] = sof;
sof ++;
}
}
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
cin >> r >> c;
for(int i = 0; i <r; i ++)
{
for(int j = 0; j < c; j ++)
{
cin >> mat[i][j];
if(mat[i][j] == 'S')
start = {i,j};
if(mat[i][j] == 'C')
arv = {i, j};
dist[i][j] = MOD;
near[i][j] = MOD;
}
}
build();
set<pair<int,pii>> pq;
pq.insert({0,start});
int ans = MOD;
while(!pq.empty())
{
pair<int,pii> u = *(pq.begin());
pq.erase(pq.begin());
int d = u.ff;
pii coord = u.ss;
int x = u.ss.ff;
int y = u.ss.ss;
//cout << x << ' ' << y << ' ' << d << '\n' << flush;
if(x == arv.ff && y == arv.ss)
{
cout << d;
return 0;
}
dist[x][y] = d;
bool wall = false;
vector<pii> wls;
int near = MOD;
for(int i= 0; i < 4; i ++)
{
int newx = nx[i] + x;
int newy = ny[i] + y;
if(newx >= 0 && newx < r && newy >= 0 && newy < c
&& dist[newx][newy] > d + 1 && mat[newx][newy] != '#')
{
pq.insert({d+1,{newx,newy}});
dist[newx][newy] = d + 1;
}
near = min(near,psa[i][x][y]);
wls.pb({x+nx[i]*psa[i][x][y],y+ny[i]*psa[i][x][y]});
}
for(auto e: wls)
{
int a = e.ff;
int b = e.ss;
if(dist[a][b] > d +near)
pq.insert({d+near,e});
dist[a][b] = min(dist[a][b],d+near);
}
}
//cout << "fin sans res\n";
return 0;
}
/*
TEST CASE:
3 7
S##...#
.......
.#...C#
Identify problem diagram: Brute force, Greedy, Dynamic Programming, Divide and Conquer
Reformulate the problem into something more theoretical
!!!!! IMPLICIT GRAPH ??????
!!!!! PAY ATTENTION TO THE CONSTRAINTS: DP nD ? BF ? BITMASKING ?
!!!!! SOLVE THE SUBTASKS FIRST: IT'S TOTALLY OK NOT TO SOLVE THE PROBLEM ENTIRELY
Search for multiple approaches: select the seemingly optimal one
Remember that you're the king of CP
Change your approach
Imagine Corner cases before submitting
Don't spend too much time on the problem: move on !
*/
Compilation message
portals.cpp:26:1: warning: multi-line comment [-Wcomment]
26 | ////////////******SOLUTION******\\\\\\\\\\\
| ^
portals.cpp: In function 'int main()':
portals.cpp:116:13: warning: variable 'coord' set but not used [-Wunused-but-set-variable]
116 | pii coord = u.ss;
| ^~~~~
portals.cpp:126:14: warning: unused variable 'wall' [-Wunused-variable]
126 | bool wall = false;
| ^~~~
portals.cpp:110:9: warning: unused variable 'ans' [-Wunused-variable]
110 | int ans = MOD;
| ^~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
332 KB |
Output is correct |
| 2 |
Correct |
1 ms |
584 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
588 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
332 KB |
Output is correct |
| 2 |
Correct |
1 ms |
588 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
580 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
332 KB |
Output is correct |
| 2 |
Correct |
1 ms |
588 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
588 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
332 KB |
Output is correct |
| 2 |
Correct |
1 ms |
588 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
588 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
332 KB |
Output is correct |
| 2 |
Correct |
0 ms |
588 KB |
Output is correct |
| 3 |
Incorrect |
1 ms |
588 KB |
Output isn't correct |
| 4 |
Halted |
0 ms |
0 KB |
- |
