417. 太平洋大西洋水流问题

src/main.rs

@@ -2,21 +2,38 @@ mod arr;
 struct Solution {}
 
 impl Solution {
-    pub fn triangle_number(nums: Vec<i32>) -> i32 {
-        if nums.len() < 3 {
-            return 0;
+    pub fn dfs(heights: &Vec<Vec<i32>>,arr: &mut Vec<Vec<bool>>,i:usize,j:usize ) {
+        let dirs = vec![(0,1),(0,-1),(1,0),(-1,0)];
+        for dir in dirs {
+            let (x,y) = (i as i32 + dir.0, j as i32 + dir.1);
+            if x>=0 && x<heights.len() as i32 && y>=0 && y<heights[0].len() as i32 && !arr[x as usize][y as usize] && heights[x as usize][y as usize]>=heights[i][j] {
+                arr[x as usize][y as usize] = true;
+                Self::dfs(heights,arr,x as usize,y as usize);
             }
-        let mut nums = nums;
-        nums.sort();
-        let mut ans = 0;
-        for i in 0..nums.len() - 2 {
-            let mut r = i + 2;
-            for l in i + 1..nums.len() - 1 {
-                while r < nums.len() && nums[i] + nums[l] > nums[r] {
-                    r += 1;
         }
-
-                ans += ((r - l) as i32 - 1).max(0);
+    }
+    pub fn pacific_atlantic(heights: Vec<Vec<i32>>) -> Vec<Vec<i32>> {
+        let (m,n) = (heights.len(),heights[0].len());
+        let mut pacific = vec![vec![false;n];m];
+        let mut atlantic = vec![vec![false;n];m];
+        let mut ans = vec![];
+        for i in 0..m {
+            pacific[i][0] = true;
+            atlantic[i][n-1] = true;
+            Self::dfs(&heights,&mut pacific,i,0);
+            Self::dfs(&heights,&mut atlantic,i,n-1);
+        }
+        for j in 0..n {
+            pacific[0][j] = true;
+            atlantic[m-1][j] = true;
+            Self::dfs(&heights,&mut pacific,0,j);
+            Self::dfs(&heights,&mut atlantic,m-1,j);
+        }
+        for i in 0..m {
+            for j in 0..n {
+                if pacific[i][j] && atlantic[i][j] {
+                    ans.push(vec![i as i32,j as i32]);
+                }
             }
         }
         ans
@@ -24,6 +41,14 @@ impl Solution {
 }
 
 fn main() {
-    let arr = vec![7, 0, 0, 0];
-    println!("{}", Solution::triangle_number(arr));
+    // [[1,2,2,3,5],[3,2,3,4,4],[2,4,5,3,1],[6,7,1,4,5],[5,1,1,2,4]]
+    // initial as a 2D vector
+    let arr = vec![
+        vec![1, 2, 2, 3, 5],
+        vec![3, 2, 3, 4, 4],
+        vec![2, 4, 5, 3, 1],
+        vec![6, 7, 1, 4, 5],
+        vec![5, 1, 1, 2, 4],
+    ];
+    println!("{:?}", Solution::pacific_atlantic(arr));
 }