题意:输出最长递增子序列的长度
思路:直接裸LIS,
</pre><pre code_snippet_id="648389" snippet_file_name="blog_20150420_4_7842089" class="sio" name="code" style="white-space: pre-wrap; word-wrap: break-word; font-size: 14px; line-height: 26px; background-color: rgb(255, 255, 255);"><pre name="code" class="cpp">#include<cstdio> const int N = 1001; int a[N], f[N], d[N]; // d[i]用于记录a[0...i]的最大长度 int bsearch(const int *f, int size, const int &a) { int l=0, r=size-1; while( l <= r ){ int mid = (l+r)/2; if( a > f[mid-1] && a <= f[mid] ) return mid;// >&&<= 换为: >= && < else if( a < f[mid] ) r = mid-1; else l = mid+1; } } int LIS(const int *a, const int &n){ int i, j, size = 1; f[0] = a[0]; d[0] = 1; for( i=1; i < n; ++i ){ if( a[i] <= f[0] ) j = 0; // <= 换为: < else if( a[i] > f[size-1] ) j = size++;// > 换为: >= else j = bsearch(f, size, a[i]); f[j] = a[i]; d[i] = j+1; } return size; } int main() { int i, n; while( scanf("%d",&n) != EOF ){ for( i=0; i < n; ++i ) scanf("%d", &a[i]); printf("%d\n", LIS(a, n)); // 求最大递增/上升子序列(如果为最大非降子序列,只需把上面的注释部分给与替换) } return 0; }
时间: 2024-10-08 19:05:11