Force deduction method summary: find classes

436. Look for the right range Medium lower_bound Method 2021/11/10

Give you an interval array intervals , among intervals[i] = [starti, endi] , And each starti all Different .
Section i Of Right section It can be recorded as an interval j , And satisfy startj >= endi , And startj To minimize the .
Returns an interval consisting of each interval i Of Right section stay intervals An array of corresponding subscripts in . If a certain interval i There is no corresponding Right section , Then subscript i The value at is set to -1 .
Example ：
Input ：intervals = [[3,4],[2,3],[1,2]]
Output ：[-1,0,1]
explain ： about [3,4] , There is no such thing as “ On the right side ” Section .
about [2,3] , Section [3,4] Have the smallest “ Right ” The starting point ;
about [1,2] , Section [2,3] Have the smallest “ Right ” The starting point .

utilize map Press... Automatically when the container is inserted key Nature of sorting , Use map Container storage intervals The left interval value and the corresponding subscript in , When traversing each interval , Use map In container lower_bound How to find key In the first >= Iterator of its right interval value , Its second Value is its subscript .