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15 lines
2.7 KiB
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15 lines
2.7 KiB
HTML
数列的片段和
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<div class="ques-view"><p>给定一个正数数列，我们可以从中截取任意的连续的几个数，称为片段。例如，给定数列 { 0.1, 0.2, 0.3, 0.4 }，我们有 (0.1) (0.1, 0.2) (0.1, 0.2, 0.3) (0.1, 0.2, 0.3, 0.4) (0.2) (0.2, 0.3) (0.2, 0.3, 0.4) (0.3) (0.3, 0.4) (0.4) 这 10 个片段。</p>
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<p>给定正整数数列，求出全部片段包含的所有的数之和。如本例中 10 个片段总和是 0.1 + 0.3 + 0.6 + 1.0 + 0.2 + 0.5 + 0.9 + 0.3 + 0.7 + 0.4 = 5.0。</p>
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<h3 id="-">输入格式：</h3>
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<p>输入第一行给出一个不超过 <span class="katex"><span class="katex-mathml"><math><mrow><mn>1</mn><msup><mn>0</mn><mn>5</mn></msup></mrow>10^5</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.8141079999999999em;"></span><span class="strut bottom" style="height:0.8141079999999999em;vertical-align:0em;"></span><span class="base textstyle uncramped"><span class="mord mathrm">1</span><span class="mord"><span class="mord mathrm">0</span><span class="msupsub"><span class="vlist"><span style="top:-0.363em;margin-right:0.05em;"><span class="fontsize-ensurer reset-size5 size5"><span style="font-size:0em;"></span></span><span class="reset-textstyle scriptstyle uncramped mtight"><span class="mord mathrm mtight">5</span></span></span><span class="baseline-fix"><span class="fontsize-ensurer reset-size5 size5"><span style="font-size:0em;"></span></span></span></span></span></span></span></span></span> 的正整数 <span class="katex"><span class="katex-mathml"><math><mrow><mi>N</mi></mrow>N</math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.68333em;"></span><span class="strut bottom" style="height:0.68333em;vertical-align:0em;"></span><span class="base textstyle uncramped"><span class="mord mathit" style="margin-right:0.10903em;">N</span></span></span></span>，表示数列中数的个数，第二行给出 <span class="katex"><span class="katex-mathml"><math><mrow><mi>N</mi></mrow>N </math></span><span aria-hidden="true" class="katex-html"><span class="strut" style="height:0.68333em;"></span><span class="strut bottom" style="height:0.68333em;vertical-align:0em;"></span><span class="base textstyle uncramped"><span class="mord mathit" style="margin-right:0.10903em;">N</span></span></span></span> 个不超过 1.0 的正数，是数列中的数，其间以空格分隔。</p>
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<h3 id="-">输出格式：</h3>
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<p>在一行中输出该序列所有片段包含的数之和，精确到小数点后 2 位。</p>
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<h3 id="-">输入样例：</h3>
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<pre><code class="lang-in">4
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0.1 0.2 0.3 0.4
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</code></pre>
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<h3 id="-">输出样例：</h3>
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<pre><code class="lang-out">5.00
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</code></pre>
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</div> |