[LeetCode] 163. Missing Ranges 缺失区间
Given a sorted integer array nums, where the range of elements are in the inclusive range [lower, upper], return its missing ranges.
Example:
Input: nums = [0, 1, 3, 50, 75], lower = 0 and upper = 99,
Output: ["2", "4->49", "51->74", "76->99"]
Java:
class Solution {
public List<String> findMissingRanges(int[] nums, int lower, int upper) {
List<String> res = new ArrayList<String>();
int next = lower;
for (int i = 0; i < nums.length; i++) {
// 1. We don't need to add [Integer.MAX_VALUE, ...] to result
if(lower == Integer.MAX_VALUE) return res;
if (nums[i] < next) {
continue;
}
if (nums[i] == next) {
next++;
continue;
}
res.add(getRange(next, nums[i] - 1));
// 2. We don't need to proceed after we have process Integer.MAX_VALUE in array
if(nums[i] == Integer.MAX_VALUE) return res;
next = nums[i] + 1;
}
if (next <= upper) {
res.add(getRange(next, upper));
}
return res;
}
public String getRange(int n1, int n2) {
return n1 == n2 ? String.valueOf(n1) : String.format("%d->%d" , n1, n2);
}
}
Java:
public class Solution {
public List<String> findMissingRanges(int[] A, int lower, int upper) {
if(A==null) return null;
List<String> res = new ArrayList<String>();
for(int i=0; i<A.length; i++) {
while(i<A.length && A[i] == lower ) {lower++; i++;}
if(i>=A.length) break;
if(A[i] == lower+1) {
res.add(String.valueOf(lower));
} else {
res.add("" + lower + "->" + (A[i]-1) );
}
lower = A[i] + 1;
}
if(lower == upper) {
res.add(String.valueOf(lower));
} else if(lower < upper ){
res.add("" + lower + "->" + upper );
}
return res;
}
}
Java:
public class Solution {
public List<String> findMissingRanges(int[] nums, int lower, int upper) {
List<String> res = new ArrayList<>();
if (nums == null || lower > upper) return res;
for (int num : nums) {
if (num - lower >= 1) res.add(getRangeString(lower, num - 1));
lower = num + 1;
}
if (lower <= upper) res.add(getRangeString(lower, upper));
return res;
}
private String getRangeString(int lower, int upper) {
if (lower == upper) return String.valueOf(lower);
StringBuilder sb = new StringBuilder();
sb.append(lower).append("->").append(upper);
return sb.toString();
}
}
Python:
class Solution(object):
def findMissingRanges(self, nums, lower, upper):
"""
:type nums: List[int]
:type lower: int
:type upper: int
:rtype: List[str]
"""
def getRange(lower, upper):
if lower == upper:
return "{}".format(lower)
else:
return "{}->{}".format(lower, upper)
ranges = []
pre = lower - 1
for i in xrange(len(nums) + 1):
if i == len(nums):
cur = upper + 1
else:
cur = nums[i]
if cur - pre >= 2:
ranges.append(getRange(pre + 1, cur - 1))
pre = cur
return ranges
C++:
class Solution {
public:
vector<string> findMissingRanges(vector<int>& nums, int lower, int upper) {
vector<string> res;
int l = lower;
for (int i = 0; i <= nums.size(); ++i) {
int r = (i < nums.size() && nums[i] <= upper) ? nums[i] : upper + 1;
if (l == r) ++l;
else if (r > l) {
res.push_back(r - l == 1 ? to_string(l) : to_string(l) + "->" + to_string(r - 1));
l = r + 1;
}
}
return res;
}
};
类似题目：
[LeetCode] 228. Summary Ranges 总结区间
