Binary Search and Binary Search

Binary Search and Binary Search

/* Binary Search for Common bs (); Lower Bounds low_bs (); upper bounds up_bs (); */# include <cstdio >#include <algorithm> using namespace std; // [l, r) int bs (int * T, int l, int r, int v) {int m; while (l <r) {m = l + (r-l)/2; // note> 1. Enclose if (T [m] = v) return m; if (T [m] <v) l = m + 1; else r = m;} return-1; //-1 indicates not found} // The first subscript l with the search value of v // indicates the range of the lower bound [l, r) from [l, r, r] int low_bs (int * T, int l, int r, int v) {int m; while (l <r) {m = l + (r-l) /2; if (T [m]> = v) r = m; else L = m + 1;} return l;} // returns a subscript r int up_bs (int * T, int l, int r, int v) after the last element of v) {int m; while (l <r) {m = l + (r-l)/2; if (T [m] <= v) {l = m + 1;} else {r = m ;}} int a [100]; int main () {int n; scanf ("% d ", & n); for (int I = 0; I <n; I ++) scanf ("% d", & a [I]); int v; scanf ("% d", & v); sort (a, a + n); // dont forget !! Printf ("a location of this element is % d \ n", bs (a, 0, n, v); printf ("[% d, % d] ", low_bs (a, 0, n, v), up_bs (a, 0, n, v)-1); // STLscanf (" % d ", & n); for (int I = 0; I <n; I ++) scanf ("% d", & a [I]); sort (, a + n); scanf ("% d", & v); printf ("lower_bound = % d \ nupper_bound = % d \ n", lower_bound (a, a + n, v)-a, upper_bound (a, a + n, v)-a); return 0 ;}

Refer to Liu rujia <getting started classic>