// perform a query the path betwwen a and b,
// where query_path is a function on ranges of hld indices
void hld_query(int a, int b) {
int a_value = 0, b_value = 0;
while (hld_root[a] != hld_root[b]) {
if (depth[hld_root[a]] < depth[hld_root[b]]) {
b_value += query_path(hld_index[hld_root[b]], hld_index[b]);
b = parent[hld_root[b]];
} else {
a_value += query_path(hld_index[hld_root[a]], hld_index[a]);
a = parent[hld_root[a]];
}
}
if (depth[a] < depth[b])
b_value += query_path(hld_index[a], hld_index[b]);
else
a_value += query_path(hld_index[b], hld_index[a]);
return a_value + b_value;
}
static void handle_msg(char *msg) {
char *opuid, *tauid, *ptr;
int flag, distance, topn;
switch(*msg) {
case 'i': //msg格式 i[SPACE]opuid['\0']
case 'f':
if(fork() == 0) {
flag = (*msg == 'i') ? 1 : 0;
opuid = msg + 2;
topn = 999;
distance = NO_PATH;
query_neighbour(flag, opuid, topn, distance);
exit(0);
}
break;
case 'd': //msg格式 d[SPACE]opuid['\0']
if(fork() == 0) {
opuid = msg + 2;
query_adiv(opuid);
exit(0);
}
break;
case 'p': //msg格式 p[SPACE]opuid[SPACE]tauid['\0']
if(fork() == 0) {
opuid = msg + 2;
ptr = strchr(opuid, ' ');
if(ptr) {
*ptr = '\0';
tauid = ptr + 1;
distance = NO_PATH;
query_path(opuid, tauid, distance);
}
exit(0);
}
break;
default:
update_friends(msg);
break;
}
}
