Problem p01453 (C++) — buggy submission, verdict: Time Limit Exceeded

#include <bits/stdc++.h>
using namespace std;

#define max(a, b) ((a) > (b) ? (a) : (b))
#define min(a, b) ((a) < (b) ? (a) : (b))

typedef long long LL;

struct position {
  LL x;
  LL y;
  LL count;
};

int main() {
  LL w, h;
  LL houkou[5] = {0, 1, 0, -1, 0};
  cin >> w >> h;
  vector<vector<LL>> field(h, vector<LL>(w));
  list<struct position> spring;
  char c;
  LL sx, sy, gx, gy;
  LL numofFloor = 0;
  for (LL i = 0; i < h; i++) {
    for (LL j = 0; j < w; j++) {
      cin >> c;
      if (c == '.') {
        field[i][j] = 1;
        numofFloor++;
      } else if (c == '#') {
        field[i][j] = 0;
      } else if (c == '*') {
        field[i][j] = 2;
        spring.push_back({j, i, 0});
      } else if (c == 's') {
        field[i][j] = 1;
        sx = j;
        sy = i;
        numofFloor++;
      } else {
        field[i][j] = 3;
        gx = j;
        gy = i;
      }
    }
  }
  vector<vector<LL>> toGoal(h, vector<LL>(w, 0));
  vector<vector<LL>> toSpring(h, vector<LL>(w, 0));
  queue<struct position> bfs;
  struct position now;
  LL nx, ny;
  bfs.push({gx, gy, 0});
  while (!bfs.empty()) {
    now = bfs.front();
    bfs.pop();
    for (LL i = 0; i < 4; i++) {
      nx = now.x + houkou[i];
      ny = now.y + houkou[i + 1];
      if (0 <= nx && nx <= w && 0 <= ny && ny <= h) {
        if (toGoal[ny][nx] == 0 && field[ny][nx] == 1) {
          toGoal[ny][nx] = now.count + 1;
          bfs.push({nx, ny, now.count + 1});
        }
      }
    }
  }
  for (auto itr = spring.begin(); itr != spring.end(); itr++) {
    bfs.push({(*itr).x, (*itr).y, 0});
  }
  while (!bfs.empty()) {
    now = bfs.front();
    bfs.pop();
    for (LL i = 0; i < 4; i++) {
      nx = now.x + houkou[i];
      ny = now.y + houkou[i + 1];
      if (0 <= nx && nx <= w && 0 <= ny && ny <= h) {
        if (toSpring[ny][nx] == 0 && field[ny][nx] == 1) {
          toSpring[ny][nx] = now.count + 1;
          bfs.push({nx, ny, now.count + 1});
        }
      }
    }
  }
  // for(LL i=0;i<h;i++){
  //   for(LL j=0;j<w;j++){
  //     cout << toGoal[i][j] << " ";
  //   }
  //   cout << endl;
  // }
  // cout << endl;
  // for(LL i=0;i<h;i++){
  //   for(LL j=0;j<w;j++){
  //     cout << toSpring[i][j] << " ";
  //   }
  //   cout << endl;
  // }
  // cout << numofFloor << endl;
  cout << fixed << setprecision(12);
  double left = 0;
  double right = 10000000000000000;
  double mid;
  double count;
  int spcount = 0;
  while (right - left > 0.0000000002 * right) {
    mid = (left + right) / 2;
    spcount = 0;
    count = 0;
    for (LL i = 1; i < h - 1; i++) {
      for (LL j = 1; j < w - 1; j++) {
        if (field[i][j] == 1) {
          if (toGoal[i][j] != 0) {
            if (toSpring[i][j] != 0) {
              if ((double)toGoal[i][j] <
                  (double)toSpring[i][j] + (double)mid / (double)numofFloor) {
                count += (double)toGoal[i][j];
              } else {
                count += (double)toSpring[i][j];
                spcount++;
              }
            } else {
              count += (double)toGoal[i][j];
            }
          } else {
            if (toSpring[i][j] != 0) {
              count += (double)toSpring[i][j];
              spcount++;
            }
          }
        }
      }
    }
    count += (double)mid * (double)spcount / (double)numofFloor;
    if (count < mid) {
      right = mid;
    } else {
      left = mid;
    }
  }
  // cout << left << endl;
  // cout << right << endl;
  // cout << count << endl;
  // cout << toSpring[sy][sx] << endl;
  // for(LL i=0;i<h;i++){
  //   for(LL j=0;j<w;j++){
  //     if(field[i][j]==1){
  //       if(toGoal[i][j]!=0){
  //         if(toSpring[i][j]!=0){
  //           cout <<
  //           min((double)toGoal[i][j],(double)toSpring[i][j]+(double)left/(double)numofFloor)
  //           << " ";
  //         }else{
  //           cout << (double)toGoal[i][j] << " ";
  //         }
  //       }else{
  //         if(toSpring[sy][sx]!=0) cout <<
  //         (double)toSpring[i][j]+(double)left/(double)numofFloor << " ";
  //       }
  //     }else{
  //       cout << 0 << " ";
  //     }
  //   }
  //   cout << endl;
  // }
  if (toGoal[sy][sx] != 0) {
    if (toSpring[sy][sx] != 0) {
      cout << min((double)toGoal[sy][sx],
                  (double)toSpring[sy][sx] + (double)left / (double)numofFloor)
           << endl;
    } else {
      cout << (double)toGoal[sy][sx] << endl;
    }
  } else {
    if (toSpring[sy][sx] != 0)
      cout << (double)toSpring[sy][sx] + (double)left / (double)numofFloor
           << endl;
  }

  return 0;
}


Error: TLE

Fixed submission:

#include <bits/stdc++.h>
using namespace std;

#define max(a, b) ((a) > (b) ? (a) : (b))
#define min(a, b) ((a) < (b) ? (a) : (b))

typedef long long LL;

struct position {
  LL x;
  LL y;
  LL count;
};

int main() {
  LL w, h;
  LL houkou[5] = {0, 1, 0, -1, 0};
  cin >> w >> h;
  vector<vector<LL>> field(h, vector<LL>(w));
  list<struct position> spring;
  char c;
  LL sx, sy, gx, gy;
  LL numofFloor = 0;
  for (LL i = 0; i < h; i++) {
    for (LL j = 0; j < w; j++) {
      cin >> c;
      if (c == '.') {
        field[i][j] = 1;
        numofFloor++;
      } else if (c == '#') {
        field[i][j] = 0;
      } else if (c == '*') {
        field[i][j] = 2;
        spring.push_back({j, i, 0});
      } else if (c == 's') {
        field[i][j] = 1;
        sx = j;
        sy = i;
        numofFloor++;
      } else {
        field[i][j] = 3;
        gx = j;
        gy = i;
      }
    }
  }
  vector<vector<LL>> toGoal(h, vector<LL>(w, 0));
  vector<vector<LL>> toSpring(h, vector<LL>(w, 0));
  queue<struct position> bfs;
  struct position now;
  LL nx, ny;
  bfs.push({gx, gy, 0});
  while (!bfs.empty()) {
    now = bfs.front();
    bfs.pop();
    for (LL i = 0; i < 4; i++) {
      nx = now.x + houkou[i];
      ny = now.y + houkou[i + 1];
      if (0 <= nx && nx <= w && 0 <= ny && ny <= h) {
        if (toGoal[ny][nx] == 0 && field[ny][nx] == 1) {
          toGoal[ny][nx] = now.count + 1;
          bfs.push({nx, ny, now.count + 1});
        }
      }
    }
  }
  for (auto itr = spring.begin(); itr != spring.end(); itr++) {
    bfs.push({(*itr).x, (*itr).y, 0});
  }
  while (!bfs.empty()) {
    now = bfs.front();
    bfs.pop();
    for (LL i = 0; i < 4; i++) {
      nx = now.x + houkou[i];
      ny = now.y + houkou[i + 1];
      if (0 <= nx && nx <= w && 0 <= ny && ny <= h) {
        if (toSpring[ny][nx] == 0 && field[ny][nx] == 1) {
          toSpring[ny][nx] = now.count + 1;
          bfs.push({nx, ny, now.count + 1});
        }
      }
    }
  }
  // for(LL i=0;i<h;i++){
  //   for(LL j=0;j<w;j++){
  //     cout << toGoal[i][j] << " ";
  //   }
  //   cout << endl;
  // }
  // cout << endl;
  // for(LL i=0;i<h;i++){
  //   for(LL j=0;j<w;j++){
  //     cout << toSpring[i][j] << " ";
  //   }
  //   cout << endl;
  // }
  // cout << numofFloor << endl;
  cout << fixed << setprecision(12);
  double left = 0;
  double right = 10000000000000000;
  double mid;
  double count;
  int spcount = 0;
  while (right - left > 0.0000000000000002 * right) {
    mid = (left + right) / 2;
    spcount = 0;
    count = 0;
    for (LL i = 1; i < h - 1; i++) {
      for (LL j = 1; j < w - 1; j++) {
        if (field[i][j] == 1) {
          if (toGoal[i][j] != 0) {
            if (toSpring[i][j] != 0) {
              if ((double)toGoal[i][j] <
                  (double)toSpring[i][j] + (double)mid / (double)numofFloor) {
                count += (double)toGoal[i][j];
              } else {
                count += (double)toSpring[i][j];
                spcount++;
              }
            } else {
              count += (double)toGoal[i][j];
            }
          } else {
            if (toSpring[i][j] != 0) {
              count += (double)toSpring[i][j];
              spcount++;
            }
          }
        }
      }
    }
    count += (double)mid * (double)spcount / (double)numofFloor;
    if (count < mid) {
      right = mid;
    } else {
      left = mid;
    }
  }
  // cout << left << endl;
  // cout << right << endl;
  // cout << count << endl;
  // cout << toSpring[sy][sx] << endl;
  // for(LL i=0;i<h;i++){
  //   for(LL j=0;j<w;j++){
  //     if(field[i][j]==1){
  //       if(toGoal[i][j]!=0){
  //         if(toSpring[i][j]!=0){
  //           cout <<
  //           min((double)toGoal[i][j],(double)toSpring[i][j]+(double)left/(double)numofFloor)
  //           << " ";
  //         }else{
  //           cout << (double)toGoal[i][j] << " ";
  //         }
  //       }else{
  //         if(toSpring[sy][sx]!=0) cout <<
  //         (double)toSpring[i][j]+(double)left/(double)numofFloor << " ";
  //       }
  //     }else{
  //       cout << 0 << " ";
  //     }
  //   }
  //   cout << endl;
  // }
  if (toGoal[sy][sx] != 0) {
    if (toSpring[sy][sx] != 0) {
      cout << min((double)toGoal[sy][sx],
                  (double)toSpring[sy][sx] + (double)left / (double)numofFloor)
           << endl;
    } else {
      cout << (double)toGoal[sy][sx] << endl;
    }
  } else {
    if (toSpring[sy][sx] != 0)
      cout << (double)toSpring[sy][sx] + (double)left / (double)numofFloor
           << endl;
  }

  return 0;
}