@@ -32,49 +32,79 @@ Output: 2
3232 All points are distinct.
3333*/
3434
35+ #define HF 1021
36+ 37+ typedef struct e_s {
38+ int y1 ;
39+ int y2 ;
40+ int x ;
41+ struct e_s * shadow ;
42+ } e_t ;
43+ 44+ typedef struct {
45+ e_t * e [HF ];
46+ e_t buff [250000 ];
47+ int n ;
48+ } h_t ;
49+ 50+ int hash_code (int y1 , int y2 ) {
51+ int hc = y1 * 33 + y2 ;
52+ return hc % HF ;
53+ }
54+ 55+ e_t * lookup (h_t * ht , int y1 , int y2 ) {
56+ int hc = hash_code (y1 , y2 );
57+ e_t * e = ht -> e [hc ];
58+ while (e && (e -> y1 != y1 || e -> y2 != y2 )) e = e -> shadow ;
59+ return e ;
60+ }
61+ 62+ void insert (h_t * ht , int y1 , int y2 , int x ) {
63+ e_t * e = & ht -> buff [ht -> n ++ ];
64+ int hc = hash_code (y1 , y2 );
65+ e -> y1 = y1 ;
66+ e -> y2 = y2 ;
67+ e -> x = x ;
68+ e -> shadow = ht -> e [hc ];
69+ ht -> e [hc ] = e ;
70+ }
71+ 3572int cmp (const void * a , const void * b ) {
36- int * p1 = * (int * * )a ;
37- int * p2 = * (int * * )b ;
38-
39- if (p1 [0 ] < p2 [0 ]) return -1 ;
40- if (p1 [0 ] > p2 [0 ]) return 1 ;
41- if (p1 [1 ] < p2 [1 ]) return -1 ;
42- return 1 ;
73+ int * p1 = * (int * * )a ;
74+ int * p2 = * (int * * )b ;
75+
76+ if (p1 [0 ] < p2 [0 ]) return -1 ;
77+ if (p1 [0 ] > p2 [0 ]) return 1 ;
78+ if (p1 [1 ] < p2 [1 ]) return -1 ;
79+ return 1 ;
4380}
44-
81+ 4582int minAreaRect (int * * points , int pointsSize , int * pointsColSize ){
46- int * a , * b , * c , * d , area , ans = 0 ;
47- 48- // x ascending, y ascending
49- qsort (points , pointsSize , sizeof (int * ), cmp );
50- 51- for (int i = 0 ; i < pointsSize ; i ++ ) {
52- a = points [i ];
53- for (int j = i + 1 ; j < pointsSize && points [j ][0 ] == a [0 ]; j ++ ) {
54- b = points [j ];
55- for (int k = j + 1 ; k < pointsSize ; k ++ ) {
56- c = points [k ];
57- if (c [1 ] == a [1 ]) {
58- for (int l = k + 1 ; l < pointsSize && points [l ][0 ] == c [0 ]; l ++ ) {
59- d = points [l ];
60- if (d [1 ] == b [1 ]) {
61- // this is a rectangle
62- area = (b [1 ] - a [1 ]) * (c [0 ] - a [0 ]);
63- if (ans == 0 || ans > area ) ans = area ;
64- goto next ;
65- }
66- }
67- 68- }
69- next :
70- b = NULL ;
71- }
72- }
73- 74- return ans ;
83+ int i , j , x , y1 , y2 , area , ans = 0 ;
84+ e_t * e ;
85+ h_t ht = { 0 };
86+ 87+ // x ascending, y ascending
88+ qsort (points , pointsSize , sizeof (int * ), cmp );
89+ 90+ for (int i = 0 ; i < pointsSize - 1 ; i ++ ) {
91+ x = points [i ][0 ];
92+ y1 = points [i ][1 ];
93+ for (j = i + 1 ; j < pointsSize && points [j ][0 ] == x ; j ++ ) {
94+ y2 = points [j ][1 ];
95+ e = lookup (& ht , y1 , y2 );
96+ if (e ) {
97+ area = (x - e -> x ) * (y2 - y1 );
98+ if (ans == 0 || ans > area ) ans = area ;
99+ e -> x = x ;
100+ } else {
101+ insert (& ht , y1 , y2 , x );
102+ }
103+ }
104+ }
105+ 106+ return ans ;
75107}
76-
77-
78108
79109
80110/*
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