算法训练营day66-孤岛总面积-沉没孤岛-水流问题-建造最大岛屿

题目1：101. 孤岛的总面积 (kamacoder.com)

#include <iostream>
#include <vector>
#include <queue>
using namespace std;
int dir[4][2] = {0,-1,-1,0,0,1,1,0};
int count = 0;
void bfs(vector<vector<int>>& map, vector<vector<bool>>& vistied, int x, int y, bool flag) {queue<pair<int, int>> qu;qu.push(pair<int, int>(x, y));vistied[x][y] = true;if(flag) map[x][y] = 0;else count++;while(!qu.empty()) {pair<int, int> cur = qu.front();qu.pop();int newx = cur.first;int newy = cur.second;for(int i = 0;i < 4;i++) {int nextx = newx + dir[i][0];int nexty = newy + dir[i][1];if(nextx < 0 || nextx >= map.size() || nexty < 0 || nexty >= map[0].size()) continue;if(!vistied[nextx][nexty] && map[nextx][nexty] == 1) {vistied[nextx][nexty] = true;qu.push(pair<int, int>(nextx, nexty));if(flag) map[nextx][nexty] = 0;else count++;}}}
}int main() {int n,m;cin >> n >> m;vector<vector<int>> map(n, vector<int>(m));for(int i = 0;i < n;i++) {for(int j = 0;j < m;j++) {cin >> map[i][j]; }}vector<vector<bool>> vistied(n, vector<bool>(m, false));for(int j = 0;j < m;j++) {if(map[0][j] == 1 && !vistied[0][j]) bfs(map, vistied, 0, j, true);if(map[n - 1][j] == 1 && !vistied[n - 1][j]) bfs(map, vistied, n - 1, j, true);}for(int i = 0;i < n;i++) {if(map[i][0] == 1 && !vistied[i][0]) bfs(map, vistied, i, 0, true);if(map[i][m - 1] == 1 && !vistied[i][m - 1]) bfs(map, vistied, i, m - 1, true);}for(int i = 0;i < n;i++) {for(int j = 0;j < m;j++) {if(!vistied[i][j] && map[i][j] == 1) {// if(i != 0 && i != n - 1 && j != 0 && j != m - 1) {//     result++;// }bfs(map,vistied,i,j, false);}}}cout << count << endl;return 0;
}

题目2：102. 沉没孤岛 (kamacoder.com)

#include <iostream>
#include <vector>
#include <queue>
using namespace std;
int dir[4][2] = {0,-1,-1,0,0,1,1,0};void bfs(vector<vector<int>>& map, vector<vector<bool>>& vistied, vector<vector<int>>& result, int x, int y, bool flag) {queue<pair<int, int>> qu;qu.push(pair<int, int>(x, y));vistied[x][y] = true;if(flag) map[x][y] = 0;else result[x][y] = 0;while(!qu.empty()) {pair<int, int> cur = qu.front();qu.pop();int newx = cur.first;int newy = cur.second;for(int i = 0;i < 4;i++) {int nextx = newx + dir[i][0];int nexty = newy + dir[i][1];if(nextx < 0 || nextx >= map.size() || nexty < 0 || nexty >= map[0].size()) continue;if(!vistied[nextx][nexty] && map[nextx][nexty] == 1) {vistied[nextx][nexty] = true;qu.push(pair<int, int>(nextx, nexty));if(flag) map[nextx][nexty] = 0;else result[nextx][nexty] = 0;}}}
}int main() {int n,m;cin >> n >> m;vector<vector<int>> map(n, vector<int>(m));vector<vector<int>> result(n, vector<int>(m));for(int i = 0;i < n;i++) {for(int j = 0;j < m;j++) {cin >> map[i][j];result[i][j] = map[i][j];}}vector<vector<bool>> vistied(n, vector<bool>(m, false));for(int j = 0;j < m;j++) {if(map[0][j] == 1 && !vistied[0][j]) bfs(map, vistied, result, 0, j, true);if(map[n - 1][j] == 1 && !vistied[n - 1][j]) bfs(map, vistied, result, n - 1, j, true);}for(int i = 0;i < n;i++) {if(map[i][0] == 1 && !vistied[i][0]) bfs(map, vistied, result, i, 0, true);if(map[i][m - 1] == 1 && !vistied[i][m - 1]) bfs(map, vistied, result, i, m - 1, true);}for(int i = 0;i < n;i++) {for(int j = 0;j < m;j++) {if(!vistied[i][j] && map[i][j] == 1) {bfs(map,vistied, result,i,j, false);}}}for(int i = 0;i < n;i++) {for(int j = 0;j < m - 1;j++) {cout << result[i][j] << ' ';}cout << result[i][m - 1] << endl;}return 0;
}

题目3：103. 水流问题 (kamacoder.com)

题目4：104. 建造最大岛屿 (kamacoder.com)