Commit b0ceac8

committed

Add Solution.java to problems 0055.

1 parent da8436b commit b0ceac8Copy full SHA for b0ceac8

File tree

+76

-5

lines changed

+76

-5

lines changed

Lines changed: 23 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,23 @@`
	`1`	`+# Jump Game`
	`2`	`+`
	`3`	`+Given an array of non-negative integers, you are initially positioned at the first index of the array.`
	`4`	`+`
	`5`	`+Each element in the array represents your maximum jump length at that position.`
	`6`	`+`
	`7`	`+Determine if you are able to reach the last index.`
	`8`	`+`
	`9`	`+`
	`10`	`+## Example 1:`
	`11`	+```
	`12`	`+ Input: [2,3,1,1,4]`
	`13`	`+ Output: true`
	`14`	`+ Explanation: Jump 1 step from index 0 to 1, then 3 steps to the last index.`
	`15`	+```
	`16`	`+`
	`17`	`+## Example 2:`
	`18`	+```
	`19`	`+ Input: [3,2,1,0,4]`
	`20`	`+ Output: false`
	`21`	`+ Explanation: You will always arrive at index 3 no matter what. Its maximum`
	`22`	`+ jump length is 0, which makes it impossible to reach the last index.`
	`23`	+```

Lines changed: 5 additions & 5 deletions

Original file line number	Diff line number	Diff line change
`@@ -1,10 +1,10 @@`
`1`	`1`	`class Solution {`
	`2`	`+`
`2`	`3`	`public boolean canJump(int[] nums) {`
`3`		`- int count=0;`
`4`		`- for(int i=nums.length-2;i>=0;i--) {`
`5`		`- if (nums[i] > count) count = 0;`
`6`		`- else count++;`
	`4`	`+ int count = 0;`
	`5`	`+ for (int i = nums.length - 2; i >= 0; i --) {`
	`6`	`+ count = nums[i] > count ? 0 : count + 1;`
`7`	`7`	`}`
`8`		`- return count==0;`
	`8`	`+ return count == 0;`
`9`	`9`	`}`
`10`	`10`	`}`

Lines changed: 16 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,16 @@`
	`1`	`+class Solution {`
	`2`	`+`
	`3`	`+ public boolean canJump(int[] nums) {`
	`4`	`+ return solution(nums.length - 1, nums);`
	`5`	`+ }`
	`6`	`+`
	`7`	`+ private boolean solution(int target, int[] nums) {`
	`8`	`+ if (target == 0) return true;`
	`9`	`+ for (int i = target - 1; i >= 0; i--) {`
	`10`	`+ if (nums[i] + i >= target) {`
	`11`	`+ return solution(i, nums);`
	`12`	`+ }`
	`13`	`+ }`
	`14`	`+ return false;`
	`15`	`+ }`
	`16`	`+}`

Lines changed: 32 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,32 @@`
	`1`	`+enum Index {`
	`2`	`+ GOOD, BOD, INIT;`
	`3`	`+}`
	`4`	`+`
	`5`	`+class Solution {`
	`6`	`+`
	`7`	`+ private Index[] indexs;`
	`8`	`+`
	`9`	`+ public boolean canJump(int[] nums) {`
	`10`	`+ this.indexs = new Index[nums.length];`
	`11`	`+ for (int i = 0; i < indexs.length; i++) {`
	`12`	`+ indexs[i] = Index.INIT;`
	`13`	`+ }`
	`14`	`+ indexs[indexs.length - 1] = Index.GOOD;`
	`15`	`+ return solution(0, nums);`
	`16`	`+ }`
	`17`	`+`
	`18`	`+ private boolean solution(int i, int[] nums) {`
	`19`	`+ if (indexs[i] != Index.INIT) {`
	`20`	`+ return indexs[i] == Index.GOOD;`
	`21`	`+ }`
	`22`	`+ int limit = Math.min(nums[i] + i, nums.length - 1);`
	`23`	`+ for (int j = i + 1; j <= limit; j ++) {`
	`24`	`+ if (solution(j, nums)) {`
	`25`	`+ indexs[i] = Index.GOOD;`
	`26`	`+ return true;`
	`27`	`+ }`
	`28`	`+ }`
	`29`	`+ indexs[i] = Index.BOD;`
	`30`	`+ return false;`
	`31`	`+ }`
	`32`	`+}`

Comments

(0)