oj.uz

Submission #519674

# Submission time Handle Problem Language Result Execution time Memory
519674 2022-01-27T03:01:46 Z zhangjishen Tracks in the Snow (BOI13_tracks) C++
100 / 100
 1297 ms 103420 KB 
#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define pf push_front
template<typename T> bool chkmin(T &a, T b){return b < a ? a = b, 1 : 0;}
template<typename T> bool chkmax(T &a, T b){return b > a ? a = b, 1 : 0;}
const int MAXN = 4e3 + 10, inf = INT_MAX;
const int mv[4][2] = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};

int n, m;
char g[MAXN][MAXN];

bool valid(int x, int y){
	return x >= 0 && x < n && y >= 0 && y < m && g[x][y] != '.';
}

inline int id(int x, int y){ return x * m + y; }
inline int x(int id){ return id / m; }
inline int y(int id){ return id % m; }

deque<int> q;
int d[MAXN * MAXN];
int bfs(){
	for(int i = 0; i < n * m; i++)
		d[i] = inf;
	d[0] = 1; q.pb(0);
	int ans = 0;
	while(!q.empty()){
		int u = q.front(); q.pop_front();
		chkmax(ans, d[u]);
		for(int k = 0; k < 4; k++){	// implicit edges
			int nx = x(u) + mv[k][0];
			int ny = y(u) + mv[k][1];
			int v = id(nx, ny);
			if(valid(nx, ny) && d[v] == inf){
				if(g[x(u)][y(u)] == g[nx][ny]){	// 0
					d[v] = d[u];
					q.pf(v);
				}else{
					d[v] = d[u] + 1;
					q.pb(v);
				}
			}
		}
	}
	return ans;
}

int main(){
	// input
	scanf("%d %d", &n, &m);
	for(int i = 0; i < n; i++)
		for(int j = 0; j < m; j++)
			scanf(" %c", &g[i][j]);
	// 0/1 bfs
	int track = bfs();
	printf("%d\n", track);
}

Compilation message

tracks.cpp: In function 'int main()':
tracks.cpp:51:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |  scanf("%d %d", &n, &m);
      |  ~~~~~^~~~~~~~~~~~~~~~~
tracks.cpp:54:9: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   54 |    scanf(" %c", &g[i][j]);
      |    ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 20 ms 3324 KB Output is correct
2 Correct 0 ms 332 KB Output is correct
3 Correct 1 ms 436 KB Output is correct
4 Correct 12 ms 2996 KB Output is correct
5 Correct 5 ms 1740 KB Output is correct
6 Correct 0 ms 332 KB Output is correct
7 Correct 1 ms 460 KB Output is correct
8 Correct 1 ms 460 KB Output is correct
9 Correct 1 ms 716 KB Output is correct
10 Correct 5 ms 1596 KB Output is correct
11 Correct 4 ms 1228 KB Output is correct
12 Correct 8 ms 1848 KB Output is correct
13 Correct 6 ms 1832 KB Output is correct
14 Correct 6 ms 1720 KB Output is correct
15 Correct 19 ms 3448 KB Output is correct
16 Correct 20 ms 3320 KB Output is correct
17 Correct 16 ms 3312 KB Output is correct
18 Correct 12 ms 3020 KB Output is correct

Subtask #2
70.0 / 70.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 15416 KB Output is correct
2 Correct 96 ms 12836 KB Output is correct
3 Correct 804 ms 94204 KB Output is correct
4 Correct 202 ms 25924 KB Output is correct
5 Correct 505 ms 56076 KB Output is correct
6 Correct 1275 ms 100900 KB Output is correct
7 Correct 9 ms 16204 KB Output is correct
8 Correct 9 ms 15428 KB Output is correct
9 Correct 5 ms 588 KB Output is correct
10 Correct 2 ms 460 KB Output is correct
11 Correct 9 ms 15940 KB Output is correct
12 Correct 2 ms 972 KB Output is correct
13 Correct 96 ms 12832 KB Output is correct
14 Correct 55 ms 8248 KB Output is correct
15 Correct 54 ms 9008 KB Output is correct
16 Correct 46 ms 4932 KB Output is correct
17 Correct 263 ms 28028 KB Output is correct
18 Correct 213 ms 27588 KB Output is correct
19 Correct 199 ms 26052 KB Output is correct
20 Correct 178 ms 23876 KB Output is correct
21 Correct 467 ms 58004 KB Output is correct
22 Correct 510 ms 56004 KB Output is correct
23 Correct 469 ms 48096 KB Output is correct
24 Correct 481 ms 57096 KB Output is correct
25 Correct 897 ms 94392 KB Output is correct
26 Correct 996 ms 99012 KB Output is correct
27 Correct 1214 ms 103420 KB Output is correct
28 Correct 1259 ms 100912 KB Output is correct
29 Correct 1289 ms 99700 KB Output is correct
30 Correct 1297 ms 101004 KB Output is correct
31 Correct 973 ms 63196 KB Output is correct
32 Correct 1226 ms 102584 KB Output is correct