【DP】 HDOJ 5009 Paint Pearls

sign。。。比赛的时候已经确定算法了。。。最后卡在实现上。。。赛后AC的。。。。

#include <iostream>  #include <queue>  #include <stack>  #include <map>  #include <set>  #include <bitset>  #include <cstdio>  #include <algorithm>  #include <cstring>  #include <climits>  #include <cstdlib>#include <cmath>#include <time.h>#define maxn 50005#define maxm 40005#define eps 1e-10#define mod 1000000007#define INF 999999999#define lowbit(x) (x&(-x))#define mp mark_pair#define ls o<<1#define rs o<<1 | 1#define lson o<<1, L, mid  #define rson o<<1 | 1, mid+1, R  typedef long long LL;//typedef int LL;using namespace std;LL qpow(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base;base=base*base;b/=2;}return res;}LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}void scanf(int &__x){__x=0;char __ch=getchar();while(__ch==' '||__ch=='\n')__ch=getchar();while(__ch>='0'&&__ch<='9')__x=__x*10+__ch-'0',__ch = getchar();}LL gcd(LL _a, LL _b){if(!_b) return _a;else return gcd(_b, _a%_b);}// headint v[maxn], vv[maxn];int pre[maxn], pos[maxn], num[maxn];int dp[maxn];int vcnt, n;int search(int x){int bot = 1, top = vcnt, mid;while(top >= bot) {mid = (top + bot) >> 1;if(vv[mid] == x) break;if(vv[mid] > x) top = mid-1;else bot = mid+1;}return mid;}int cmp(int a, int b){return a < b;}void init(void){memset(dp, 0, sizeof dp);memset(pre, -1, sizeof pre);memset(pos, -1, sizeof pos);memset(num, -1, sizeof num);}void read(void){for(int i = 1; i <= n; i++) scanf("%d", &v[i]), vv[i] = v[i];int j = 2;sort(vv+1, vv+n+1, cmp);for(int i = 2; i <= n; i++)if(vv[i] != vv[i-1]) vv[j++] = vv[i];vcnt = j - 1;for(int i = 1; i <= n; i++) v[i] = search(v[i]);}void work(void){int t = sqrt((double)n);t += 2;for(int i = 1; i <= n; i++) pre[i] = num[v[i]], num[v[i]] = i;for(int i = 1; i <= n; i++) {dp[i] = dp[i-1] + 1;if(pre[i] == -1) {for(int k = t; k >= 2; k--) pos[k] = pos[k-1];pos[1] = i;}else {for(int k = t; k >= 2; k--)if(pos[k] <= pre[i]) continue;else pos[k] = pos[k-1];if(v[i] != v[i-1]) pos[1] = i;}pos[t] = -1;for(int k = 1; k <= t; k++) {if(pos[k] == -1) break;else dp[i] = min(dp[pos[k]-1] + k * k, dp[i]);}}printf("%d\n", dp[n]);}int main(void){while(scanf("%d", &n)!=EOF) {init();read();work();}return 0;}