66 */
77var countRangeSum = function ( nums , lower , upper ) {
88 const len = nums . length ;
9+ const v = [ 0 ] ;
910
10- 11- } ;
11+ for ( let i = 0 ; i < len ; i ++ ) {
12+ v . push ( v [ i ] + nums [ i ] ) ;
13+ }
14+ let raw_nums = v . slice ( ) ;
15+ const copy_nums = v . slice ( ) ;
16+ // console.log(v)
17+ 18+ const merge_sort = ( lo , hi , lower , upper ) => {
19+ if ( hi - lo <= 1 ) return 0 ;
20+ 21+ let mid = lo + parseInt ( ( hi - lo ) / 2 ) ;
22+ let count = merge_sort ( lo , mid , lower , upper ) + merge_sort ( mid , hi , lower , upper ) ;
23+ let right1 = mid , right2 = mid ;
24+ 25+ for ( let left = lo ; left < mid ; left ++ ) {
26+ while ( right1 != hi && raw_nums [ right1 ] - raw_nums [ left ] < lower ) right1 ++ ;
27+ while ( right2 != hi && raw_nums [ right2 ] - raw_nums [ left ] <= upper ) right2 ++ ;
28+ 29+ count += right2 - right1 ;
30+ }
31+ 32+ // console.log('----', lo, mid, hi)
33+ // merge
34+ let index = lo ;
35+ let li = lo , ri = mid ;
36+ while ( index < hi ) {
37+ // console.log(li, ri, 'index is', index)
38+ if ( li === mid ) {
39+ copy_nums [ index ] = raw_nums [ ri ++ ] ;
40+ } else if ( ri === hi ) {
41+ copy_nums [ index ] = raw_nums [ li ++ ] ;
42+ } else if ( raw_nums [ li ] < raw_nums [ ri ] ) {
43+ copy_nums [ index ] = raw_nums [ li ++ ] ;
44+ } else {
45+ copy_nums [ index ] = raw_nums [ ri ++ ] ;
46+ }
47+ index ++ ;
48+ // console.log(copy_nums)
49+ }
50+ // console.log(copy_nums);
51+ raw_nums = copy_nums . slice ( ) ;
52+ 53+ // console.log(count);
54+ return count ;
55+ }
56+ 57+ return merge_sort ( 0 , v . length , lower , upper ) ;
58+ } ;
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