Submission #26479

#	Time	Username	Problem	Language	Result	Execution time	Memory
26479		zoomswk	Split the sequence (APIO14_sequence)	C++14	100 / 100	1796 ms	83540 KiB

sequence

#include <stdio.h>

int min(int a, int b){ return a < b ? a : b; }

int n;
long long a[100005];
long long dp[100005][2];
int opt[100005][205];

void conquer(int l, int r, int lv, int opt_l, int opt_r){
    if(l > r) return;
    int mid = (l+r)>>1;
    for(int i=opt_l; i<=min(mid-1, opt_r); i++){
        long long val = dp[i][(lv-1)&1] + (a[mid]-a[i])*(a[n]-a[mid]);
        if(val >= dp[mid][lv&1]) dp[mid][lv&1] = val, opt[mid][lv] = i;
    }
    conquer(l, mid-1, lv, opt_l, opt[mid][lv]);
    conquer(mid+1, r, lv, opt[mid][lv], opt_r);
    return;
}

int main(){
    int k;
    scanf("%d%d", &n, &k);
    for(int i=1; i<=n; i++) scanf("%lld", &a[i]), a[i] += a[i-1];
    for(int i=1; i<=k; i++){
        for(int j=1; j<=n; j++) dp[j][i&1] = 0;
        conquer(1, n, i, 0, n);
    }
    long long res = 0;
    int res_pos = 0;
    for(int i=1; i<n; i++){
        if(dp[i][k&1] >= res){
            res = dp[i][k&1];
            res_pos = i;
        }
    }
    printf("%lld\n", res);
    while(k){
        printf("%d ", res_pos);
        res_pos = opt[res_pos][k];
        k--;
    }
    return 0;
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:24:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &n, &k);
                          ^
sequence.cpp:25:65: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for(int i=1; i<=n; i++) scanf("%lld", &a[i]), a[i] += a[i-1];
                                                                 ^

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 21 / 21
• Subtask 6: 29 / 29