ソフトウェアエンジニアの技術ブログ：Software engineer tech blog

use std::collections::HashMap;
use std::collections::VecDeque;

fn bfs(graph: HashMap<&str, Vec<&str>>, start: &str) {
   let mut deque: VecDeque<&str> = VecDeque::new();
   let mut visited: Vec<&str> = Vec::new();

   deque.push_back(start);

   while !deque.is_empty() {
      let vertex = deque.pop_front().unwrap();
      if !visited.contains(&vertex) {
         visited.push(vertex);
         if graph.get(vertex) != None {
            let vs = graph.get(vertex).unwrap();
            for v in vs {
               // println!("{}", v);
               deque.push_back(v);
            }
         }
      }
   }
}


fn main() {
   let mut graph: HashMap<&str, Vec<&str>> = HashMap::new();

   graph.insert("A", vec!["B", "C"]);
   graph.insert("B", vec!["A", "D", "E"]);
   graph.insert("C", vec!["A", "F"]);
   graph.insert("D", vec!["B"]);
   graph.insert("E", vec!["B", "F"]);
   graph.insert("F", vec!["C", "E"]);

   println!("{:?}", graph);

   bfs(graph, "A");
}

#[derive(Debug)]
struct Edge {
   to: i32,
   cost: i32,
}


fn main() {
   let V = 3;
   let E = 3;

   let matrix = [[0,1], [0,2], [1,2]];
   let mut edges: Vec<Edge> = Vec::new();

   for i in 0..E {
      let ed = Edge { to: matrix[i][0], cost: matrix[i][1]};
      edges.push(ed);
   }

   println!("{:?}", edges);
}

fn main() {
   let mut N = 4; // gas station num
   let P = 10; // initial gas
   let L = 25; // distance

   let mut A: Vec<i32> = vec![10, 14, 20, 21]; // gas station distance
   let mut B: Vec<i32> = vec![10, 5, 2, 4]; // gas volume supply

   A.push(L);
   B.push(0);
   N += 1;

   let que; // manage gas station

   let mut ans = 0; // num of gas supply
   let mut pos = 0; // position
   let mut tank = P; // gas volume

   for i in 0..N {
      let d = A[i] - pos; // distance

      while (tank - d < 0) {
         if que.empty() {
            que.push(-1);
            return;
         }
         tank += que.top();
         que.pop();
         ans += 1;
      }

      tank -= d;
      pos = A[i];
      que.push(B[i]);
   }
   println!("{}", ans);
}

priority queはstackで大きい順に値を入れていく。

fn push(x: i32) {
   let mut heap = [1, 2, 3, 4, 5, 6, 7, 8];
   let sz = 0;
   let mut i = sz + 1;

   while(i > 0) {
      let p = (i -1) / 2;

      if heap[p] <= x {
         break;
      }

      heap[i] = heap[p];
      i = p;
   }
   heap[i] = x;
}

fn pop() {
   let mut heap = [1, 2, 3, 4, 5, 6, 7, 8];
   let sz = 0;

   let ret = heap[0];
   let x = heap[heap.len() -1];

   let mut i = 0;
   while(i * 2 + 1 < sz) {
      let mut a = i * 2 + 1;
      let mut b = i * 2 + 2;
      if (b < sz && heap[b] < heap[a]) {
         a = b;
      }
      if (heap[a] >= x) {
         break;
      }

      heap[i] = heap[a];
      i = a;
   }
   heap[i] = x;
}

use std::collections::HashMap;

fn rec (i: i32, j: i32) -> i32{

   let n = 4;
   let w = [
      [2,3],
      [1,2],
      [3,4],
      [2,2]
   ];
   let res;
   if(i == n) {
      res = 0;
   } else if (j < w[i as usize][0]) {
      res = rec(i + 1, j);
   } else {
      res = std::cmp::max(rec(i + 1, j), rec(i + 1, j - w[i as usize][0]) + w[i as usize][1]);
   }
   return res;
}

fn main() {
   let W = 5;
   let res = rec(0, W);
   println!("{}", res);
}

Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.52s
Running `target/debug/basic`
7

hashmapではなく、多次元配列にする必要あり

const N: i32 = 10;
const M: i32 = 12;

fn dfs(x: i32, y: i32) {
   field[x][y] = ".".to_string();

   for (let dx in -1..1) {
      for (let dy in -1..1) {
         let nx = x + dx;
         let ny = y + dy;

         if(0 <= nx && nx < N && 0 <= ny && ny < M && field[nx][ny] == 'W') {
            dfs(nx, ny);
         }
      }
   }
}


fn main() {
   let field[N, M];
   let mut res = 0;
   for i in 0..N {
      for j in 0..M {
         if field[i][j] == 'W' {
            dfs(i, j);
            res =+ 1;
         }
      }
   }
   println!("{}", res);
}

fn dfs(i: i32, sum: i32) -> bool {
   let k = 10;
   let n = 10;

   if (i == n) {
      return sum == k;
   }

   if (dfs(i + 1, sum)) {
      return true;
   }

   if (dfs(i + 1, sum + i)) {
      return true;
   }
   return false;
}


fn main() {
   if (dfs (0, 0)) {
      println!("yes");
   } else {
      println!("no");
   }
}

fn main() {
   let n = 10;
   let L = 100;
   let mut minT: i32 = 0;

   for i in 0..n {
      minT = std::cmp::max(minT, i.min(L - i));
   }

   let mut maxT: i32 = 0;
   for i in 0..n {
      maxT = std::cmp::max(minT, std::cmp::max(i, L - i));
   }

   println!("max:{}, min: {}", minT, maxT);

}

max:9, min: 91