poj 1631 Bridging signals (DP_最長遞增子序列nlogn)

題目大意：給定1個序列，不會重復，x出現在y位置，即代表x與y可以連線。最後要從這個序列中儘量多地選擇連線並保證連線不交叉。

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

#define MAXN    40001

int v[MAXN], f[MAXN], idx;

int binary_search(int x)
{
        int l(0), r(idx-1), m;
        if( !idx || x > f[idx-1] ) {
                f[idx ++] = x; return idx;
        }
        while( l <= r ) {
                m = (l+r)>>1;
                if( f[m] < x ) {
                        l = m+1;
                }
                else if( f[m] > x ) {
                        r = m-1;
                }
        }
        if( l >= 0 && l < idx ) {
                f[l] = x; return idx;
        }
        if( r >= 0 && r < idx ) {
                f[r] = x; return idx;
        }
}

int main(int argc, char const *argv[])
{
#ifndef ONLINE_JUDGE
        freopen("test.in", "r", stdin);
#endif
        int cas, n, rst;
        scanf("%d", &cas);
        for( ; cas; cas --) {
                scanf("%d", &n); rst = idx = 0;
                for(int i = 1; i <= n; i ++) {
                        scanf("%d", &v[i]);
                }
                for(int i = 1; i <= n; i ++) {
                        rst = max(rst, binary_search(v[i]));
                }
                printf("%d\n", rst);
        }
        return 0;
}