greedy

Author: caibirdme

src/lib.rs

@@ -80,6 +80,8 @@ mod prob_125;
 mod prob_127;
 mod prob_131;
 mod prob_132;
+mod prob_134;
+mod prob_135;
 mod prob_144;
 mod prob_149;
 mod prob_159;

src/prob_134.rs

@@ -0,0 +1,48 @@
+
+impl Solution {
+    pub fn can_complete_circuit(gas: Vec<i32>, cost: Vec<i32>) -> i32 {
+        if gas.iter().sum::<i32>() < cost.iter().sum() {
+            return -1;
+        }
+        let mut ans = -1;
+        let mut rest = 0;
+        let mut i = 0;
+        while i < gas.len() {
+            if ans == -1 && gas[i]<cost[i] {
+                i+=1;
+                continue;
+            }
+            if ans == -1 {
+                rest = gas[i] - cost[i];
+                ans = i as i32;
+                i+=1;
+            } else {
+                rest += gas[i] - cost[i];
+                if rest < 0 {
+                    ans = -1;
+                } else {
+                    i+=1;
+                }
+            }
+        }
+        ans
+    }
+}
+
+struct Solution;
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    #[test]
+    fn test_can_complete_circuit() {
+        let test_cases = vec![
+            (vec![1,2,3,4,5], vec![3,4,5,1,2], 3),
+            (vec![2,3,4], vec![3,4,3], -1),
+        ];
+        for (gas, cost, expect) in test_cases {
+            assert_eq!(Solution::can_complete_circuit(gas.clone(), cost.clone()), expect, "gas: {:?}, cost: {:?}", gas, cost);
+        }
+    }
+}

src/prob_135.rs

@@ -0,0 +1,42 @@
+impl Solution {
+    pub fn candy(ratings: Vec<i32>) -> i32 {
+        let n = ratings.len();
+        if n < 2 {
+            return n as i32;
+        }
+        let mut v = vec![1; n];
+
+        for i in 1..n {
+            if ratings[i] > ratings[i-1] {v[i] = v[i-1]+1;}
+        }
+        for i in (0..n-1).rev() {
+            if ratings[i] > ratings[i+1] {v[i] = v[i].max(v[i+1]+1);}
+        }
+        v.iter().sum()
+    }
+}
+
+struct Solution;
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    #[test]
+    fn test_candy() {
+        let test_cases = vec![
+            (vec![1,0,2],5),
+            (vec![1,2,3,4,4,3,2,1], 20),
+            (vec![1,2,3,4,3,2,1], 16),
+            (vec![5,4,3,2,1], 15),
+            (vec![5,5,5,5,5], 5),
+            (vec![5,4,4,3,3,3], 8),
+            (vec![5,4,4,3,3,8], 9),
+            (vec![5,4,4,3,3,2], 9),
+            (vec![1,2,2],4),
+        ];
+        for (ratings, expect) in test_cases {
+            assert_eq!(Solution::candy(ratings.clone()), expect, "ratings: {:?}", ratings);
+        }
+    }
+}