質問編集履歴
1
参考にした他の人のコードを追記しました。
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File without changes
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body
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@@ -68,4 +68,74 @@
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68
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}
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cout << ans << endl;
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70
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}
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71
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```
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### 参考にしたコード
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74
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```
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75
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#include <iostream>
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76
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#include <algorithm>
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77
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#include <string>
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78
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#include <vector>
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79
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#include <cmath>
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80
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#include <map>
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81
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#include <queue>
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82
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#include <iomanip>
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83
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#include <set>
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84
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#include <tuple>
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85
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#define mkp make_pair
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86
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#define mkt make_tuple
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87
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#define rep(i,n) for(int i = 0; i < (n); ++i)
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88
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using namespace std;
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89
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typedef long long ll;
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90
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const ll MOD=1e9+7;
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91
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92
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ll N,M;
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93
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vector<ll> A;
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94
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+
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95
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vector<ll> sum;
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96
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97
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bool judge(ll lim){
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98
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ll res=0;
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99
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int itr=0;
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100
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for(int i=N-1;i>=0;i--){
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101
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while(itr<N&&A[i]+A[itr]>=lim){
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102
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itr++;
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103
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}
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104
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res+=itr;
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105
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}
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106
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107
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if(res>=M) return true;
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108
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else return false;
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109
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}
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110
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+
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111
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int main(){
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112
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cin>>N>>M;
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113
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A.resize(N);
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114
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rep(i,N) cin>>A[i];
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115
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116
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sort(A.rbegin(),A.rend());
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117
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118
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sum.resize(N+1,0);
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119
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rep(i,N) sum[i+1]=sum[i]+A[i];
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120
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+
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121
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ll ok=0,ng=(A[0]*2+1)*M;
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122
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while(abs(ok-ng)>1){
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123
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ll mid=(ok+ng)/2;
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124
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if(judge(mid)) ok=mid;
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125
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else ng=mid;
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126
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}
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127
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+
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128
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ll ans=0;
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129
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ll itr=0;
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130
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ll num=0;
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131
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for(int i=N-1;i>=0;i--){
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132
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while(itr<N && A[i]+A[itr]>=ok) itr++;
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133
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ans+=A[i]*itr+sum[itr];
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134
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num+=itr;
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135
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}
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136
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ans-=ok*(num-M);
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137
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cout<<ans<<endl;
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138
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139
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return 0;
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140
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}
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71
141
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```
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