Uva12086-potentiometer (line segment tree/tree array)

Uva12086-potentiometer (line segment tree/tree array)

Question Link

Give you n numbers and then have Q operations. Operation Type: M indicates modifying the value of a certain position to R, and s indicates querying the numbers and values of a certain segment.

Solution: Line Segment tree or tree array.

Line Segment tree

#include <cstdio>#include <cstring>const int N = 8e5 + 5;int v[N];int n;int Query (int o, int l, int r, int ql, int qr) {    int    m = l + (r - l) / 2;    if (ql == l && r == qr)        return v[o];     if (qr <= m)        return Query(2 * o, l, m, ql, qr);    else if (ql > m)        return Query(2 * o + 1, m + 1, r, ql, qr);    else         return Query(2 * o, l, m, ql, m) + Query(2 * o + 1, m + 1, r, m + 1, qr);}void Update (int o, int l, int r, int p, int val) {    int m = l + (r - l) / 2;    if (l == r)         v[o] = val;    else {        if (p <= m)            Update (2 * o, l, m, p, val);        else            Update (2 * o + 1, m + 1, r, p, val);        v[o] = v[2 * o] + v[2 * o + 1];    }}void solve () {    char str[10];    int x, y, r;    while (scanf ("%s", str) && str[0] != ‘E‘) {        if (str[0] == ‘M‘) {            scanf ("%d%d", &x, &y);            printf ("%d\n", Query (1, 1, n, x, y));        } else {            scanf ("%d%d", &x, &r);            Update (1, 1, n, x, r);            }    }}int main () {    int cas = 0;    int num;    while (scanf ("%d", &n) && n) {        if (cas)            printf ("\n");        printf ("Case %d:\n", ++cas);        memset (v, 0, sizeof (v));        for (int i = 1; i <= n; i++) {            scanf ("%d", &num);            Update (1, 1, n, i, num);        }        solve();                }    return 0;}

Tree Array

# Include <cstdio >#include <cstring> const int maxn = 2e5 + 5; int lowbit (int x) {return X &-X;} int N; int A [maxn], C [maxn]; void add (int x, int d) {While (x <= N) {C [x] + = D; X + = lowbit (x) ;}} int sum (int x) {int ret = 0; while (x> 0) {RET + = C [x]; x-= lowbit (x);} return ret;} void solve () {char STR [10]; int X, R, Y; while (scanf ("% s ", str) & STR [0]! = 'E') {If (STR [0] = 'M') {scanf ("% d", & X, & Y ); printf ("% d \ n", sum (y)-sum (X-1);} else {scanf ("% d", & X, & R); add (x, R-A [x]); A [x] = r; // remember to modify this part.} int main () {int CAS = 0; while (scanf ("% d", & N) {If (CAS) printf ("\ n"); memset (C, 0, sizeof (c); For (INT I = 1; I <= N; I ++) {scanf ("% d", & A [I]); add (I, a [I]);} printf ("case % d: \ n", ++ CAS); solve ();} return 0 ;}

Uva12086-potentiometer (line segment tree/tree array)