贪心

Author: haotf

134.加油站.java

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+/*
+ * @lc app=leetcode.cn id=134 lang=java
+ *
+ * [134] 加油站
+ */
+
+// @lc code=start
+class Solution {
+    public int canCompleteCircuit(int[] gas, int[] cost) {
+        int sum = 0;
+        int tank = 0;
+        int start = 0;
+        for (int i = 0; i < cost.length; i++) {
+            sum = sum + gas[i] - cost[i];
+            tank = tank + gas[i] - cost[i];
+            if (tank < 0) {
+                tank = 0;
+                start = i + 1;
+            }
+        }
+        if (sum < 0 || start == gas.length)
+            return -1;
+        return start;
+    }
+}
+// @lc code=end

45.跳跃游戏-ii.java

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+/*
+ * @lc app=leetcode.cn id=45 lang=java
+ *
+ * [45] 跳跃游戏 II
+ */
+
+// @lc code=start
+class Solution {
+    public int jump(int[] nums) {
+        int len = nums.length;
+        int farthest = 0;
+        int step = 0;
+        int point = 0;
+
+        for (int i = 0; i < len - 1; i++) {
+            farthest = Math.max(farthest, i + nums[i]);
+            if (point == i) {
+                point = farthest;
+                step++;
+            }
+        }
+        return step;
+    }
+}
+// @lc code=end

55.跳跃游戏.java

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+/*
+ * @lc app=leetcode.cn id=55 lang=java
+ *
+ * [55] 跳跃游戏
+ */
+
+// @lc code=start
+class Solution {
+    public boolean canJump(int[] nums) {
+        if (nums.length == 0)
+            return true;
+        int len = nums.length;
+        int farthest = 0;
+
+        for (int i = 0; i < len - 1; i++) {
+            farthest = Math.max(farthest, i + nums[i]);
+            if (farthest <= i)
+                return false;
+        }
+
+        return farthest >= len - 1;
+    }
+}
+// @lc code=end